Comparing Customer Acquisition Costs: Amazon vs. Google vs. Meta for E-commerce Brands

Understanding Customer Acquisition Metrics

For e-commerce brands, customer acquisition costs (CAC) are critical to understanding the efficiency of your marketing channels. Across Amazon, Google, and Meta, you'll commonly use metrics such as Cost Per Acquisition (CPA) and Return on Ad Spend (ROAS) to evaluate performance. These figures help determine if your ad spend is profitable, whether the channel is scalable, and where to focus investment.

Factoring in Channel-Specific Costs

While CPA and ROAS are important, they don’t paint the whole picture. Amazon, particularly when using Fulfilled by Amazon (FBA), includes additional fees per sale. These must be included in profitability calculations. Google and Meta typically direct traffic to Shopify stores, which incur fewer fees, making ROAS a more reliable metric for overall performance. You need to calculate a ROAS that works in-line with your margins and AOV though, benchmarks aren’t useful as a 4:1 might look good on paper but doesn’t economically stack up for your brand.

Google Ads: High Intent, High Competition

Google Ads is one of the most powerful platforms for e-commerce due to its demand capture capabilities. Users actively searching for products exhibit high intent, which leads to high conversion rates. However, competition is intense in many verticals, driving up cost-per-click (CPC) and potentially raising customer acquisition costs. Despite this, higher conversion rates may offset the cost. Optimizing your website’s conversion rate and increasing average order value can further improve efficiency.

Meta Ads: Demand Generation at Scale

Unlike Google, Meta (Facebook and Instagram) excels at generating demand. You can target those similar to existing customers, reaching users before they search who are looking to buy. Meta offers lower CPCs and CPMs, but typically sees lower conversion rates. With the right creatives and campaign structure, Meta becomes a valuable channel to scale sales profitably.

To get Meta to perform commercially, you need conversion data to guide the algorithm. Your role is to support the system in finding the right person, not to perfectly define them through targeting (how we would years ago).

A sales focused creative which outlines what the product is and the problem it solves is essential. Fluffy brand focused creatives don’t lead to sales which means the data isn’t going back into the algorithm to guide bidding.

Own Your Data and Increase Long-Term ROI

Google and Meta ads driving traffic to Shopify provide access to valuable customer data. With user consent, you can run retention campaigns via email and SMS, launch referral programs, and build loyalty. Meta activity also boosts your social following and brand awareness over time, contributing to a sustainable marketing ecosystem. This is something which isn’t taken into account when it comes to in-channel metrics such as CPA, CAC, ROAS or TACOS.

Amazon’s Role in the Mix

Amazon is still essential. Some customers will always prefer to buy on Amazon for the convenience, even after discovering your brand through Google or Meta ads. External ad activity can increase branded searches and sales on Amazon, and vice versa. Being present across all three platforms ensures maximum visibility and reach.

Speed of Execution and Conversion Optimization

Amazon offers quick go-to-market capabilities with minimal work on conversion optimization, design, or development. In contrast, success on Shopify requires building an effective site experience first, which may involve short-term costs. Over time, however, Shopify generally delivers lower blended acquisition costs due to reduced fees.

Final Thoughts: Use All Three Channels Together for the best blended CAC

Evaluating channels purely on customer acquisition cost misses key nuances.

True profitability depends on net margin after platform fees, conversion rates, and the ability to retain customers.

Amazon, Google, and Meta are not either/or choices - they work best together. A multi-channel approach delivers compounding benefits, feeding into each other to scale your e-commerce brand profitably over the mid to long term.