Google Ads for ecommerce: sales with control of margin

A high ROAS does not automatically mean a profitable shop. ROAS ignores margin, shipping, returns, promotions and fulfilment costs, so we judge campaigns on profit as well as revenue. Good campaigns earn revenue at a cost that accounts for margin, returns, seasonality and customer lifetime value.

Double Digital is a Google Premier Partner 2026 (top 3% of Google Ads agencies in Poland). We combine Google Shopping, Performance Max, Search and remarketing, analyse results by product, category and market, and treat the feed, analytics and store UX as part of the scope. One team handles ads, feed, analytics and UX.

Merchant Center passes product, price, availability, shipping and store data to Google. Errors limit serving or send people to outdated offers, so we monitor disapproved and limited products, price consistency with product pages, stock, shipping and return settings, identifier quality and domain alignment.

The feed is more than a product list. Titles, descriptions, images, categories, brand, identifiers and custom labels for margin, season or potential all shape what you can control, and it needs ongoing optimisation.

Segmenting your range is what makes performance measurable. Without it, one average number hides your winners and losers.

Passing revenue alone can push high-volume, low-profit products. We split campaigns by margin band, label products by profitability, set different ROAS goals per category and report high- and low-profit products separately. Even a basic split beats treating the whole catalogue the same.

Blended ROAS usually overstates performance, because returning customers would have bought anyway. We measure new-customer acquisition cost separately from returning-customer revenue, alongside repurchase frequency and the products that start the customer relationship.

Tracking needs transaction value, order ID, products, quantities and coupons. Typical faults are duplicate transactions, missing value or currency, thank-you page reloads counted as orders and gaps in consent management. Automated bidding scales spend on bad signals if tracking is wrong, and last click alone hides the role that video, Shopping, search and remarketing play in one purchase.

Budget depends on catalogue size, demand, CPC, margin, the number of markets and the sales target. Set the starting budget from the number of orders you need to evaluate the campaign, not from what you are willing to spend. A new campaign typically needs roughly €7 to €11 per day (PLN 30 to 50) to collect enough data. At a 2% conversion rate one sale needs about 50 clicks, so at a CPC of €0.34 (PLN 1.50) an order costs about €17 (PLN 75) in ads. That only pays off if the margin on the basket is higher.

Third-party benchmarks for the Polish market put Shopping clicks from about €0.11 (PLN 0.50) and Search clicks typically at €0.25 to €0.45 (PLN 1 to 2), with the most competitive queries above €10 (PLN 50). Treat them as orders of magnitude: CPC only means something next to conversion rate and average order value.

Raising the budget at the same target ROAS typically lowers ROAS, because the algorithm moves into more expensive and less relevant traffic once the best queries are used up. That is normal. Scaling means accepting a lower ROAS target for more volume, as long as it stays above break-even. We scale gradually and check stock, profitability, cost of sale and the share of new customers.

Ads bring the right people, but the product page closes the sale: clear photos and video, price and availability, shipping and returns information, reviews, simple variant selection and fast mobile performance. A higher conversion rate raises the value of the same traffic, so UX fixes can beat a bigger budget.

Campaigns should follow your sales calendar: seasonal peaks, new collections, Black Friday and holidays, clearance, price changes, stock levels and delivery times. Scaling out-of-stock products wastes budget. In new markets, each country needs its own analysis of product names, price competitiveness, shipping cost and time, payment methods, returns, language and feed, plus a separate budget and profitability assessment. Read more about our approach to ecommerce marketing.