3 Most Misunderstood Principles of PPC Advertising on Amazon

One of the most underutilized and misunderstood tools on Amazon is pay-per-click (PPC) advertising. Most sellers know they need to advertise their products, but many still miss the basic principles that make those efforts work. They don’t know what keywords are most important to bid for in their PPC campaigns or how many keywords they should be bidding on. Many sellers also don’t know how much to spend on a given product, whether to use dynamic bidding, or what type of PPC campaigns to run.

Here’s the thing: PPC is a recipe that calls for just the right amount of each ingredient or it can go sour in a hurry. That recipe changes from one product or campaign to the next, which is what makes PPC difficult to get right every time. However, there are 3 guiding principles that, when properly understood and implemented, will help you be more successful with your ad spend on Amazon.

Principle #1: More Spend Doesn't Mean More Growth

Amazon advertising can create meaningful growth, but simply increasing spend is not a strategy. Start with the broader business objective: Are you trying to launch a product, acquire new customers, defend branded demand, or scale an established ASIN? Your advertising strategy should follow that objective, with budget directed toward the opportunities most likely to create efficient growth.

That means resisting the urge to treat a bigger budget as the answer to every performance problem. As spend increases, efficiency can eventually decline. The goal is to understand where additional investment is still creating meaningful business growth - and where it is simply costing more to capture demand you already had.

Amazon Ads recommends defining campaign goals first and then selecting the KPIs that align with those goals, rather than evaluating every campaign against the same measure of success.

Principle #2: Focus on Incremental Growth

Strong PPC performance isn't just about capturing sales that were likely to happen anyway. The bigger opportunity is incremental growth: using advertising to reach new shoppers, create additional demand, and identify where paid media is actually adding customers and sales to the business.

Keyword strategy still matters, but the question shouldn't only be which terms produce the most attributed sales. Look at which campaigns, audiences, and search terms are expanding the customer base and creating growth beyond existing demand. Amazon's new-to-brand metrics can help advertisers measure ad-attributed purchases from first-time customers and understand how effectively campaigns are reaching new customers.

Amazon Ads also provides Brand Metrics and long-term sales measurement for eligible advertisers, giving brands additional ways to evaluate customer engagement and the longer-term impact of acquiring new-to-brand shoppers.

Principle #3: ROAS Doesn't Tell the Whole Story

Before you create a campaign, know what each metric can - and can't - tell you. Return on ad spend (ROAS) measures attributed ad revenue against ad spend, while ACoS measures ad spend as a percentage of attributed ad sales. Both are useful measures of campaign efficiency, but neither tells you on its own whether the overall Amazon business is growing.

A campaign can show a strong ROAS while much of that revenue comes from demand the brand may already have captured. That's why we also look at Total Advertising Cost of Sales (TACoS), which compares advertising spend with total Amazon sales rather than only ad-attributed sales. Looking at TACoS alongside ROAS and ACoS helps connect advertising investment to the broader relationship between paid and organic sales.

At Buy Box Experts, the goal isn't to optimize one metric in isolation. We want to understand whether advertising is contributing to incremental demand, reaching new customers, and helping the total Amazon business grow efficiently.

Amazon's current campaign reporting supports a broader measurement approach, including ACoS, ROAS, new-to-brand metrics, long-term sales, and other measures that can be aligned to different campaign objectives.

Put These Principles Into Action 

Now that you know these three guiding principles, you have a stronger foundation for building your next Amazon campaign. There is much more to PPC than these three principles, but they should shape how you think about investment, incremental growth, and performance measurement. If you need help building and managing your PPC ads, we're more than happy to help. The Buy Box Experts ad team has extensive experience with PPC and can help you improve your performance as a seller on Amazon, so send us a note.

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