OC Systems Agency
Google Ads for E-Commerce

Google Ads for E-Commerce

Shopping, Performance Max and Merchant Center — managed against margin, not clicks

You build the product. We run the channel that sells it. Shopping and Performance Max are only as good as the product feed underneath them and the purchase event behind them, so we fix both before touching a bid — then set ROAS targets from what an order actually earns you rather than from a number that sounded ambitious.

Google ShoppingPerformance MaxMerchant CenterProduct feed managementSearch campaignsPurchase trackingShopify integration
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Where an e-commerce ad account leaks

These are the things we find on nearly every account we are handed. None of them is exotic, and none shows up as an error message — they show up as a ROAS figure that never quite makes sense against the bank balance.

  • ✗Products disapproved or quietly excluded in Merchant Center, so your best SKUs never enter the auction
  • ✗A feed left at the app default — truncated titles, missing GTINs, no product type, one custom label across the whole catalog
  • ✗Performance Max buying your own brand searches and reporting them back to you as new revenue
  • ✗Purchases counted twice, once by the Google tag and once by a Shopify app, so ROAS reads better than reality
  • ✗Target ROAS set on revenue while shipping, payment fees and returns stay outside the number
  • ✗Shopping budget spread evenly across SKUs earning 8% and SKUs earning 60%
  • ✗Ads still serving on out-of-stock variants because availability syncs once a day
  • ✗Search campaigns on broad match with no negatives, buying research queries and competitor names

The compounding problem is that the first two items make the rest unmeasurable. If the purchase event is wrong, every optimisation after it is a confident decision made on a wrong number — and Smart Bidding will act on that number faster and more thoroughly than any human would. That is the mechanism by which accounts lose money for months while the dashboard reports success.

What Google Ads Management Includes

Purchase conversion tracking rebuilt first — real order value, deduplicated against Shopify, reconciled with GA4
Merchant Center cleared: disapprovals, warnings, price and availability mismatches, tax and shipping setup
Product feed managed as an asset — titles, attributes, GTINs, product types, supplemental feeds
Custom labels by margin band, best-seller status and stock cover, so bidding can tell your SKUs apart
Shopping structure that separates priority products from the long tail instead of one campaign for everything
Performance Max run with brand exclusions, controlled asset groups and listing groups you can actually see
Search campaigns with match type and negative keyword discipline, reviewed on a fixed cadence
Target ROAS derived from contribution margin, and revisited when your costs move
New-customer value applied where your repeat-purchase data supports bidding on it
Promotions, sale price annotations and product review feeds set up where you qualify
Shopify integration checked end to end — feed, tag, consent mode, and the product pages the ads point at
Monthly reporting in plain language: spend, revenue, ROAS, and contribution after ad cost

From Your Product Data to a Tracked Sale

Every link in this chain is somebody's job. When an e-commerce account underperforms it is almost always because one of them belongs to nobody.

From Your Product Data to a Tracked Sale1Product data leaves Shopify — title, price, availability,images2Feed rules fix titles, attributes, identifiers and producttypes3Merchant Center validates the feed and flags what it will notshow4Custom labels group SKUs by margin, stock cover and priority5Shopping and Performance Max bid on those groups, not on aflat catalog6The shopper lands on the product page they were actually shown7The purchase fires once, with real order value, deduplicated8That value trains Smart Bidding, which can only be as good asit

The Feed Is the Campaign

In search you write the ad. In Shopping and Performance Max, Google writes it from your product data — so the feed is the creative, the keyword list and the eligibility check at once. Most underperforming e-commerce accounts we open have a competent-looking campaign sitting on top of a feed nobody has touched since the app installed it.

Titles and attributes

Shopping matches on the feed, not on your product page. Titles get rewritten to lead with the terms buyers actually search, and the attributes Google matches on — brand, GTIN, MPN, condition, size, colour, material, product type and Google product category — get filled in rather than left to a theme default.

Custom labels that let bidding tell SKUs apart

Margin band, best-seller status, stock cover, seasonality and clearance status become labels. Without them every SKU looks identical to Smart Bidding, which is how an 8% margin product ends up receiving the same budget treatment as a 60% margin one.

Diagnostics as a standing job

Disapprovals, warnings, price and availability mismatches, tax and shipping configuration, and the items excluded quietly for a missing identifier. A disapproved product is not a warning notice — it is a best-seller that has stopped entering the auction, and nobody notices until revenue moves.

Supplemental feeds and promotions

Where the platform will not output an attribute natively, a supplemental feed supplies it instead of the catalog being re-keyed by hand. Sale price annotations, promotions and product review feeds get set up where you qualify for them.

What a ROAS Target Actually Has to Clear

A ROAS figure is revenue divided by ad spend, and revenue is not money you keep. Before a target means anything, the cost of the goods, the pick and pack, the shipping, the payment fees and the returns have to come out of it. Only then can you say what a click is allowed to cost.

So we do not start from a ROAS target. We start from contribution per order, derive the break-even, and set the target above it by whatever margin you want to keep. The same arithmetic decides which SKUs deserve budget, which is why the custom labels in the feed matter as much as the bid strategy sitting on top of them.

Worked illustration

Made-up figures, not a client account. Substitute your own and the method is identical.

Average order value
$80.00
Cost of goods
−$26.00
Pick, pack and shipping
−$9.00
Payment processing at 2.9% + $0.30
−$2.62
Returns allowance at 6%
−$4.80
Contribution before advertising
$37.58
Break-even ROAS — where an extra order earns nothing
2.13
At a 3.0 target, what an order leaves
$10.91

Two things follow. A campaign running at a 2.0 ROAS on this unit is losing money while looking like it works, and a blanket 4.0 target across the whole catalog would starve perfectly good products with fatter margins. Neither error is visible in the Google Ads interface, because Google only ever sees the revenue number.

Where the business case supports it we also apply a new-customer value, so acquisition is bid on what a first order is worth over a customer relationship rather than on the single transaction. That is a decision made with your repeat-purchase data, not a default we switch on to make the reporting look better.

Secondary service

Google Ads for Local Service Businesses

We still run Search and Local Services Ads for local service businesses, and the discipline is the same one described above: verify the conversion tracking before touching a bid, cut the search terms that will never become customers, then scale what converts. It is simply not where most of our Google work sits — this is an e-commerce agency, and the campaigns above are what we are set up to run.

One thing worth knowing before you start on Local Services Ads: you pay per lead, so an unanswered call still costs you. That makes it a strong channel for a business that answers the phone reliably and an expensive one for a business that does not. If the answer rate is the real problem, that gets fixed first — otherwise the channel amplifies the leak rather than the revenue.

How We Run the Account

1

Fix the measurement

Purchases tracked once, with the real order value, deduplicated between the Google tag and any Shopify app, and reconciled against what your store actually recorded. Consent mode configured properly. Until this is right, everything downstream is a confident decision on a wrong number.

2

Fix the feed and the structure

Merchant Center cleared, titles and attributes rewritten, custom labels applied, then the campaigns rebuilt on top: priority SKUs separated from the long tail, brand exclusions on Performance Max, negatives applied on Search.

3

Bid to margin, then scale

Targets derived from contribution per order rather than revenue, budget moved toward the product groups clearing them, and a plain-English monthly report on spend, revenue, ROAS and what was left. Including the months where the recommendation is to spend less.

What It Costs

Flat fees, excluding the ad spend you pay Google directly. Never a percentage of your budget — under that model an agency earns more the more you spend, which makes the one conversation you most need it to have the one it is paid to avoid.

Start here

Full PPC Audit

The complete written audit of your existing account: conversion tracking checked end to end, Merchant Center and feed health, campaign structure and search-term waste, ROAS against your actual margin, and a prioritised 90-day action plan you can hand to anyone — including a different agency. Credited toward your first month if you hire us within 30 days.

$495 one-time

Ongoing

Google Ads Management

Everything on this page run month to month: tracking maintained, Merchant Center and feed managed, Shopping, Performance Max and Search structured and bid against your margin, with plain-English reporting.

$750 per month, starting + ad spend

If the store needs it too

Website + Google Management

The campaigns plus the Shopify store they point at — product pages, collections, landing pages, conversion work driven by campaign data, on-page SEO and schema. The right choice when the page is the constraint rather than the traffic.

$2,000 per month, starting + ad spend

Further reading

All Google Ads & Shopping articles →

Frequently Asked Questions

How much should an e-commerce brand spend on Google Ads?
Work backwards from what an order earns you rather than picking a budget and hoping. Take your average order value, subtract cost of goods, pick and pack, shipping, payment fees and a returns allowance, and what remains is what a sale can afford to spend on advertising. Divide the order value by that figure and you have your break-even return on ad spend — the number a campaign has to clear before it contributes anything at all. Then look at the cost per click in your category and work out how many clicks your budget actually buys. As a practical floor, you want enough spend to produce roughly 30 purchases a month, because below that Smart Bidding is learning from noise and so are we. If your category makes that impossible at the budget you have, we will say so and point you at Shopping alone, or at organic and marketplace demand, rather than take a fee to spend it badly.
Shopping or Performance Max — which should I be running?
Usually both, and the question matters less than the feed sitting underneath them. Standard Shopping gives you visible search terms, negative keywords and product-level control, which makes it the better instrument while you are still learning what people search before they buy. Performance Max reaches inventory Shopping cannot and tends to win where conversion volume is already healthy, but it spends confidently against whatever signal you hand it and shows you comparatively little about where the money went. Two conditions before we run it. Brand exclusions, so it does not buy traffic that would have arrived free and then report it to you as growth. And asset groups and listing groups we control, rather than one group holding your entire catalog. If the purchase tracking is not verified we fix that first — running Performance Max on a broken conversion event is how an account loses money quietly for months.
Why do my products keep getting disapproved in Merchant Center?
Usually one of four things, and none of them is Google being arbitrary. Price and availability mismatches between the feed and the live product page are the most common, and they resolve by fixing the crawl rather than by resubmitting and hoping. Missing or invalid GTINs on branded products get items excluded rather than disapproved, so they disappear from Shopping quietly without an obvious error anywhere. Policy issues in restricted categories need the listing changed rather than appealed. And a misconfigured tax or shipping setting can suppress an entire account while every individual product still looks fine. We work the diagnostics as a standing task rather than when somebody notices revenue dropped, because a disapproved product is a best-seller that stopped entering the auction. Where your platform will not output an attribute natively, a supplemental feed supplies it — which is where most stubborn cases end.
Do you take a percentage of ad spend?
No. The fee is flat and it does not move with your budget, which is deliberate rather than a pricing gimmick. Under a percentage model an agency's revenue rises automatically whenever your spend rises, whether or not that extra spend was profitable, so the easiest way for it to grow is to recommend a bigger budget and the hardest conversation it can have is telling you to spend less. Under a flat fee we earn exactly the same at $5,000 a month as at $50,000, which means recommending a cut costs us nothing. We will still tell you honestly when a percentage model would be cheaper for you in absolute terms — below roughly $25,000 a month in spend, a 3% fee is less than our $750 starting price, and we would rather you ran that arithmetic yourself than took our word for which model suits you.
Can you work on my existing account?
Yes, and in most cases we prefer it. An existing account carries history — conversion data, search-term reports, quality signals — that a new account has to rebuild from nothing, and that history is genuinely valuable. What we do first is audit rather than rebuild: check whether conversion tracking is actually firing and counting the right things, look for wasted spend on terms that have never converted, and see whether the structure lets the data be read at all. Frequently the account does not need replacing so much as it needs the tracking fixed and the waste stopped. You keep ownership of the account throughout, and if you leave, it stays yours with the structure and history intact — no rebuilt-from-scratch account you cannot take anywhere, which is a genuine lock-in tactic in this industry and one worth asking any agency about before you sign.
Do you still run Google Ads for local service businesses?
Yes, though it is no longer the centre of what we do. OC Systems Agency is an e-commerce growth and management agency, so most of our Google work is Shopping, Performance Max, Merchant Center and feed management for product brands. We do still run Search and Local Services Ads for local service businesses, and the discipline transfers cleanly: verify the conversion tracking, cut the search terms that will never become customers, then scale what converts. The thing worth knowing about Local Services Ads before you start is that you pay per lead, so an unanswered call still costs you. That makes it an excellent channel for a business that answers the phone reliably and an expensive one for a business that does not. If the answer rate is the real constraint, fix that first — the channel amplifies whichever of the two you have.

Last reviewed by the OC Systems Agency team.

The break-even panel on this page is a worked illustration using invented figures, not a client account or a projection. We publish no performance data, and nothing here should be read as a guaranteed ROAS, cost per acquisition or revenue outcome — results depend on your margin, category, product pages and inventory, none of which an agency controls.

Find Out What Your Ad Budget Is Actually Earning

Tell us what you sell, what you spend and roughly what an order leaves you after costs. We will show you what your break-even ROAS really is and where the account is leaking — including the case where the answer is that you do not need us.

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