If you run a small retail business and you're starting to think about paid advertising, you'll quickly come across two big names — Google Ads and Amazon Ads. Both can drive sales. Both involve paying to appear in front of customers. But they work very differently, attract customers at different stages of their buying journey, and suit different types of businesses.
This guide explains the core differences in plain language — so you can make an informed decision about where to start, or how to use both effectively.
The Fundamental Difference
Here's the simplest way to think about it:
Google is where people go to search for information and find solutions. Someone types "best running shoes for flat feet" and Google shows them a mix of articles, websites and ads. They might be browsing, researching or ready to buy — but they haven't committed yet.
Amazon is where people go to buy things. Someone types "running shoes size 9 wide" and Amazon shows them products they can add to a basket immediately. The intent is almost always purchase-ready.
That single difference in intent shapes everything — the type of ads you run, how you measure success, what you pay per click, and what results you should expect.
Head to Head — The Key Differences
| Google Ads | Amazon Ads | |
|---|---|---|
| What is it? | Ads across Google Search, YouTube, Gmail and millions of partner websites | Ads within Amazon's marketplace — search results, product pages, homepage |
| Where do customers start? | Anywhere in the buying journey — discovery, research, comparison or purchase | Usually ready to buy — they're already in a shopping environment |
| Where do ads link to? | Your own website or landing page | Your product listing on Amazon |
| Who controls the experience? | You — your site, your design, your checkout | Amazon — their platform, their checkout, their rules |
| What do you need to start? | A website and Google Ads account | An active Amazon seller account with live listings |
| How is success measured? | Clicks, website visits, conversions, ROAS | Sales, ACoS (Advertising Cost of Sale), ROAS |
| How competitive is it? | Very — billions spent globally, competitive keywords are expensive | Growing fast — but often less competitive for niche products |
| Do you own the customer data? | Yes — email addresses, purchase history, retargeting data | No — Amazon owns the customer relationship |
| Best for | Building your brand, driving traffic, retargeting, new customer acquisition | Boosting product visibility and sales within Amazon's existing audience |
The Intent Gap — Why This Matters
The most important concept to understand is purchase intent — how ready someone is to buy when they see your ad.
A customer searching "best coffee grinder under £50" is researching. They might buy today, or in three weeks after reading five reviews. Google Ads gets you in front of them early — but you need a good website, strong product pages and sometimes a few touchpoints before they convert. The journey is longer but you own the relationship.
A customer searching "coffee grinder burr 50g" on Amazon already has their wallet out. Amazon Ads puts your product in front of them at exactly the right moment. Conversion rates tend to be higher because the intent is clearer — but you're competing on price, reviews and listing quality, and Amazon keeps the customer relationship.
What Small Retailers Should Know About Costs
Both platforms use an auction model — you bid against other advertisers for the chance to show your ad. But the economics feel different in practice.
With Google Ads, you typically pay per click to your website. How much depends on your industry and how competitive the keywords are. For broad retail categories, costs per click can range from 20p to several pounds. You control your budget tightly and can start small — even £5–10 per day will generate data to learn from.
With Amazon Ads, the key metric is ACoS — Advertising Cost of Sale. This is the percentage of a sale's revenue that you spent on advertising to generate it. If you sold a £20 product and spent £4 on ads to get that sale, your ACoS is 20%. Whether that's good or bad depends entirely on your margin. If your product margin is 30%, an ACoS of 20% leaves you 10% profit. If your margin is 15%, you're losing money on every ad-driven sale.
The bottom line: you need to know your margins before you advertise on either platform.
The Data Ownership Question — Bigger Than It Sounds
This is the part most small retailers overlook when they start selling on Amazon. When someone buys through your Google Ads campaign and lands on your website, you capture their email address, can retarget them with future ads, and can build a long-term direct relationship. That customer is yours.
When someone buys your product on Amazon, Amazon owns that relationship. You don't get the customer's email address. You can't retarget them. If you ever stop selling on Amazon, that customer has no way to find you directly. You've made a sale — but Amazon has made a customer.
This isn't a reason to avoid Amazon. It's a reason to be clear-eyed about what you're building. Amazon can be a powerful sales channel — but it shouldn't be your only channel if you want to build a brand and a loyal customer base.
Which Should You Start With?
You Sell From Your Own Website
If you have your own ecommerce store and you want to drive traffic to it, Google is the natural starting point. Shopping Ads (the product images that appear at the top of Google search results) are particularly effective for retailers — they show your product, price and image directly in the search results.
You're Already Selling on Amazon
If you have an Amazon seller account with active listings, Amazon Sponsored Products ads are the quickest way to get more visibility. They're relatively straightforward to set up, and because customers are already in a buying mindset, you can see results quickly. Just make sure your listings are optimised — good photos, clear titles, strong reviews — before you pay to send traffic to them.
You Want to Build a Sustainable Business
The smartest long-term approach for most small retailers is to use both — but for different purposes. Use Amazon to capture ready-to-buy customers where you can. Use Google (and your own website) to build your brand, generate repeat customers and create a relationship that Amazon can't own. The two platforms complement each other when used strategically.
- Google reaches people across the full buying journey — Amazon reaches people who are ready to buy right now
- Google drives traffic to your website — Amazon drives sales within Amazon's platform
- With Google you own the customer relationship — with Amazon, Amazon does
- Know your margins before you advertise on either platform — especially on Amazon where ACoS is the key metric
- The best long-term strategy usually involves both — Amazon for volume, your own site for brand and loyalty
Paid advertising is one of the most effective tools available to small retailers — but it works best when you understand what each platform is actually doing for you. Start small, measure carefully, and make decisions based on data rather than assumption.
If you're not sure where to start or how to structure your first campaigns, feel free to get in touch — I'm happy to have an honest conversation about what's likely to work for your business.