Why Flat-Fee Amazon Management Beats % of Ad Spend

If your Amazon agency charges a % of ad spend, their incentive is to spend more — not to help you profit more. Here's why that model is broken and what to look for instead.

The % of ad spend model is the standard in the Amazon agency world. Agencies charge anywhere from 10% to 20% of whatever you spend on PPC. On the surface, it sounds performance-linked. In practice, it creates a dangerous misalignment.

The Incentive Problem

When an agency earns more money every time your ad spend goes up, what do you think they're optimizing for? Their goal — consciously or not — is to increase your spend, not your profit. High ACOS? Let's increase bids to compete. Poor ROAS? Let's add more campaigns.

Scaling spend is easy. Scaling profitably is hard. The % model rewards the former, not the latter.

What a Flat Fee Actually Aligns

With a flat monthly fee, an agency's incentive is retention — keeping you happy enough to stay. That means delivering actual results. Cutting wasted spend. Improving ACOS. Growing revenue without growing your ad budget unnecessarily.

• You know your cost every month, regardless of ad activity
• Agency is motivated to make your budget work harder, not bigger
• Easier to forecast and budget quarterly
• No perverse incentive to launch unnecessary campaigns

The Questions to Ask Any Amazon Agency

1. What is your fee structure and what does it include?
2. How do you report on ACOS, TACOS, and organic rank?
3. What happens to my account if I reduce ad spend?
4. Can I see examples of accounts where you reduced spend and improved profitability?

At CommerceKind, we charge one flat monthly fee. No percentage of ad spend, no hidden costs. Our job is to make your account perform — and that only happens when your results are our only metric.