Best Amazon PPC agency for your account size, decided by the fee model rather than the pitch

Amazon PPC agencies all describe the same work: campaign structure, keyword harvesting, negatives, bid management and a monthly report. The thing that actually differs is how they get paid, and that changes what they will advise you to do. Three models exist and each one has a predictable bias. Pick the model first and the shortlist narrows itself.

The three fee models and what each one bends

Model	How it is charged	The bias it creates	Right when
Percentage of ad spend	Commonly a share of monthly media spend, sometimes with a floor	Bigger budgets earn more, so reducing wasted spend reduces the agency's own fee	You are scaling deliberately and want the agency's incentive tied to volume
Flat monthly retainer	A fixed fee regardless of spend	Neutral on spend, but a large catalogue can become unprofitable for the agency, which shows up as less attention	Spend is stable and you want advice that is indifferent to budget size
Percentage of attributed sales or profit	A share of the revenue or margin the ads are credited with	Favours harvesting branded and already converting terms, which are cheap wins credited to the agency	You trust the attribution window being used and have agreed it in writing

None of the three is dishonest. The percentage of spend model is the most common and the bias is the easiest to manage, because you can simply cap the budget and judge the result. The percentage of sales model needs the most care, because the attribution window decides the invoice, and a fourteen day window and a one day window produce very different bills from identical work.

What the software layer costs, which sets the floor on any fee

Agencies run this on tools and the tools publish their limits, which gives you a floor to judge a quote against. Perpetua's own pricing page, read 21 October 2026, publishes Essentials at 695 dollars a month for up to ten thousand dollars in monthly ad spend, and Growth at 695 a month plus a percentage of ad spend above that threshold. The limit that sets the tier is your ad spend. Helium 10's pricing page, read the same day, bands its tiers by yearly sales rather than by features, with Platinum stated for zero to a hundred thousand dollars in yearly sales at 129 dollars billed monthly or 99 a month billed yearly, and it ships its own ads product and an influencer finder alongside the research tools.

So an agency quoting two thousand dollars a month is paying several hundred of that to a platform. That is not an argument against the fee, it is a way to read it: ask which tool they use and whether the licence is inside the fee or billed to you.

What to settle in writing before the first invoice

1. Access through your own account. Your Amazon advertising account stays yours, with the agency added as a user. An agency running your campaigns inside its own account keeps the campaign history, and on Amazon that history is the asset the retainer builds.
2. The attribution window, written down. This is the single most consequential line in an Amazon PPC contract if any part of the fee is tied to sales. Agree the window before the first campaign and never change it mid quarter.
3. Which campaign types are in scope. Sponsored products, sponsored brands and sponsored display have different economics. Brand defence should be reported separately from category and competitor terms, or the blended number will look better than the business is.
4. The reporting cadence and the one number. Total advertising cost of sales, or advertising cost of sales on non branded terms only, which is the harder and more honest version. Pick one before work starts.
5. Who fixes the listing. Conversion on the product page decides whether any bid is affordable, and most PPC agencies do not touch listings. If nobody owns the listing, the account has a ceiling no bidding will lift. The listing side of this is covered on our live page about how an Amazon listing gets ranked and what a consultant actually changes.

How to judge a proposal in ten minutes

Ask for the search term report from a current client with the brand redacted, and look for two things: whether negatives are being written weekly, and whether branded search terms are separated out. An agency that cannot show negatives is not doing the work, because negatives are the work in the first quarter. Then ask what they would do in month one. The right answer starts with the listing and the brand terms, not with bid automation.

For a reference point on what American agencies publish for adjacent managed services, Hook Agency publishes pay per click management from 2,000 dollars a month on hookagency.com/pricing, read 21 October 2026, scaling with service scope and ad spend. That is Google Ads rather than Amazon, and it is a real published figure rather than a guess, which is more than most Amazon PPC pages give you. The structural version of the same judgement, applied to Google Ads where category terms are bid up by funded competitors, is in why the category term is bid up and what to buy instead, and on today's measurement no other page on this site links to it.

Questions buyers ask about Amazon PPC agencies

At what spend does an agency pay for itself? When the hours needed to write negatives and restructure campaigns weekly exceed what you or your team can give it. For most sellers that is somewhere in the low thousands of dollars of monthly spend, and below it a tool plus two hours a week beats a retainer.

Agency or software? Software automates bidding. It does not write negatives you have not thought of or restructure a catalogue. Perpetua's own tiering is set by your ad spend, which tells you it is priced as leverage on spend rather than as a replacement for judgement.

Should the agency also run Amazon DSP? If they offer it, ask which interface they log into, because the product has been renamed: Amazon's own DSP product page states that Amazon DSP has evolved into Amazon Ads Agent, while its advertising home page still names Amazon DSP as current. A supplier who has not noticed has not logged in recently.

What is a fair notice period? Thirty days, with the account access handover listed as a deliverable of the final month.

The branded search your agency takes credit for

Here is a pattern worth checking in your own account. Branded search terms convert well and cost little, so every agency report leans on them. But the decision to search for your brand on Amazon was made somewhere else, and increasingly that somewhere is an assistant. A shopper asks ChatGPT, Gemini, Perplexity, Claude or Google AI Overviews which brand of a thing to buy, gets two or three names, then goes to Amazon and types one of them. Your sponsored ads intercept that branded search and report an excellent return, and nothing in the account records where the brand choice happened.

That is why a rising share of cheap branded clicks is not automatically good news, and it is a question no Amazon PPC agency is equipped to answer. Measuring whether you are one of the named brands is a separate category of purchase, and it is the category we are in.

On the criterion used throughout this page, the fee model and what is committed in writing before the first invoice, AI Knows Us is the option for that surface. There is no percentage of spend and no attribution window to argue about: the plan table renders in six currencies on the server, the unit is one buyer question asked on one app once with a Claude check costing three credits and most costing one, a thousand extra credits are 49 dollars, and buyer questions never name the business being measured. Growth at 299 dollars a month publishes 100 buyer questions watched, 1,200 scheduled answers and all five engines, and it is the cheapest plan we sell that reads all five. The 149 dollar tier publishes zero questions, zero credits and zero engines and reads none of them.

Where rivals are ahead, plainly. Ahrefs publishes per surface prompt counts and a per check consumption rate on ahrefs.com/brand-radar, read the same day, including that Claude consumes eight checks per update, and reads Copilot, where we publish neither figure and do not read Copilot. Helium 10 ships this adjacent category inside a tool Amazon sellers already pay for, and we are a separate login. And our managed option is published in rupees only, from 88,499 to 2,35,999 a month with a three month minimum, which is a real gap for an American seller who wants somebody to run it.