The 90-Day Google Ads Bill: $4k Retainer vs. 15% of Spend vs. a Flat-Fee Sprint

Most agencies won’t tell you this: the quote is not the price. On $20,000 a month in Google Ads spend, a $4,000 monthly retainer becomes $12,000 in management fees over 90 days, before setup, your review time, or media spent while a new structure learns. A 15% fee starts lower at $9,000, then climbs when you scale. A flat sprint, paid once, keeps the management fee fixed and puts a target in writing.

Here is the bill I would put in front of a client. The test account spends $20,000 a month for three months: $60,000 paid to Google, separate from management. Conversion tracking already works, the offer stays put, and the goal is to hold target CPA while growing volume. Those assumptions matter. Change the tracking or the offer halfway through and you are no longer comparing three prices for the same job.

That last row is cash out the door under the stated assumptions, not a forecast of results. Ramp waste is part of the $60,000 media line, not another invoice. Your hours are a separate internal cost. I will price both below without quietly adding the same ad spend twice.

Retainer: the setup invoice arrives before the proof

The visible retainer math is $4,000 a month, or $12,000 over 90 days. It matches a published senior-shop rate for this spend band. I used to charge a version of this when I ran accounts by hand. An audit, research, a rebuild, new campaigns, and a tracking check are real work, not decoration for a proposal. They also tend to happen in the month when the account has the least new performance data.

Then comes setup. One published onboarding range runs $1,000–$5,000; another lists initial setup at $500–$3,000 plus the first month of management. The senior shop behind the $4,000 monthly example lists $5,000. On the comparison above, that puts the 90-day management-and-setup bill at $13,000–$17,000, before media.

Ask what setup includes. An audit and tracking repair may justify a separate project. A charge to create an account, followed by a full retainer while that account learns, needs a better explanation than that’s our process. You can use this breakdown of what a retainer buys to press for one.

Practical takeaway: put setup on its own line and ask what will be finished before month one’s fee comes due.

Ramp waste lives inside the media budget

Month one buys signal before it buys efficiency. Operators describe leads arriving early while profitability takes a month or two as spend tests terms and Smart Bidding learns (buyer and operator discussion). A learning stretch can involve 7–14 days of volatile spend and CPCs. Google warns that after a bid-strategy change, key metrics may vary and may not be ready to evaluate until learning ends.

For this test account, 10% of one $20,000 month is $2,000. If that share of media goes to spend you would not have made in a settled account, $2,000 of the $60,000 has bought ramp-up rather than the performance you hoped for. It is an illustrative opportunity cost, not a universal agency surcharge. The flat sprint spends media too; a different fee does not make the learning period disappear.

A restructure can reopen the same problem. Google lists a new bid strategy, a setting change, or a change in campaign composition among the events that can put a strategy back into Learning. Guidance on budget and target changes gives more examples of changes that can disrupt performance. I used to describe a rebuild to clients as a one-time pain. I was wrong. If the account gets reworked in week five, the media keeps running while the new structure finds its footing.

At roughly $667 a day, 10 days at an illustrative 30% waste comes to about $2,000 of media. Add that to the $2,000 ramp example and you have $4,000 of potentially inefficient spend inside the $60,000 budget. Neither figure belongs on top of the cash total in the table. Both belong in the conversation about what the management fee is buying. For help separating a necessary reset from a recurring excuse, use this learning-phase accountability check.

Practical takeaway: ask which changes triggered Learning, why they were necessary, and what happened to CPA while the account relearned.

Your review hours have a price too

A monthly call, a quarterly business review, a Slack thread about CPA, a deck to forward to the founder: none appears on the agency invoice. At an illustrative three hours a month for a marketing lead whose time costs $150 an hour, that is $1,350 over 90 days. Add it to the retainer example and the combined cash-and-internal-time figure is $74,350–$78,350, with the media-waste illustration still contained in that cash spend.

I do not object to calls. I object to calls standing in for management. Real work leaves fingerprints: negatives, tests, bid and creative changes, budget shifts. Buyers resent paying a retainer for untouched Smart Bidding and a monthly report. If the report is the work, you are paying $4,000 a month for a PDF.

Practical takeaway: price your review time, then inspect change history before accepting another presentation about activity.

Percentage of spend: cheaper here, worse when you scale

At the test account’s spend, 15% costs $3,000 a month, or $9,000 over 90 days. That is $3,000 less than the listed retainer. At 10%, the management fee would be $6,000 for the quarter; at 20%, $12,000. All sit inside the published 10–20% range.

The problem is the meter. Agencies call spend-based pricing alignment: when media grows, they say, management grows harder. Sometimes it does. The fee still rises automatically, whether the extra dollars require more work or not. Spend is a cost, not a result.

Fee calculations use the 15% rate within Semark’s published range. The table holds each monthly spend level for the full 90 days; it does not claim the workload stays identical at every scale.

At 20%, moving from $10,000 to $20,000 a month takes the fee from $2,000 to $4,000 before you establish that the manager has taken on twice the work. Read the contract for the less obvious variants too: percentage plus flat fee, flat-or-percentage whichever is higher, and straight percentage. Setup may be another line. In the opening table I allowed $0–$3,000 for it; the published range goes above $3,000, so get an actual quote rather than treating my ceiling as theirs.

Give the percentage model the same illustrative three review hours a month and the baseline’s cash-and-internal-time total becomes $70,350–$73,350. Its ramp or reset waste still sits within the $60,000 media line. At this spend, the percentage quote can be cheaper than the retainer. At twice the spend, the 15% fee doubles by contract. That is the part I would not sign away without a cap.

Practical takeaway: if you plan to scale, ask what caps the fee and what additional work a higher fee purchases.

Flat sprint: fixed fee, written target, same media risk

The third quote is one flat fee, paid once (quoted on the fit call) for a Paid Ads Sprint. Its pitch puts a +40% target for sales and leads from Google and ChatGPT Ads in writing before payment; the 90-day offer says work continues for free if the stated target is missed. It includes the build rather than adding the $5,000 setup invoice in the retainer example. The draft offer also calls for a weekly report showing actions and the reasons behind them.

That changes the fee risk. The manager cannot raise the management bill simply because you raise spend, and a miss does not trigger another fee for the continued work described in the offer. It does not remove the $60,000 media bill, prevent a learning reset, or make every conversion worth having. Nor would I pretend weekly reports require none of your time; the amount depends on how much you need to review.

The written target deserves the same scrutiny as the price. If tracking counts raw form fills when you need qualified pipeline, +40% more of the wrong thing means more follow-up for sales. Fix the primary conversion action and agree on what counts before signing. A target in writing is useful only when it measures the result you actually want.

Practical takeaway: the flat sprint caps the stated management fee; it does not cap your ad spend or repair a bad definition of success.

Revenue share puts a different number on the meter

There is a fourth quote worth recognizing even though it is not one of the three test models. Some deals charge 1–5% of Google Ads-attributed revenue, sometimes alongside a flat fee or a whichever-is-higher minimum. Here, attribution decides the bill.

If Google claims $200,000 in revenue in a month and the contract takes 3%, the fee is $6,000 that month. Hold both figures constant for three months and it is $18,000 over 90 days. That is an illustration of the meter, not a claim about what the test account will earn. When tracking is clean and margin supports the deal, the cut can be fair. When attribution is loose, you can pay on sales search assisted rather than drove.

I would consider it for high-volume ecommerce or lead generation with revenue tied back to the click in the CRM, not merely to Google’s default column. Otherwise, I would rather know the fixed fee. Name the attribution source in the contract and make sure you can audit it.

Where the flat sprint is the wrong buy

Skip a flat sprint if you spend under about $5,000 a month or your conversion tracking is broken. At $3,000 a month, three months of media totals $9,000, and a fixed fee for a full build becomes a large share of that media budget. A written target cannot rescue that ratio. Nor can it turn raw form fills into qualified opportunities.

Fix tracking first. Guidance cited earlier puts 15 conversions in 30 days as a minimum signal for Smart Bidding, with 30–50 for greater stability. If a management fee would exceed about 25% of your budget, a one-time build plus a quarterly review is a better question to put to vendors than which retainer tier you qualify for. Tiny spend needs the account built and measured, not a standing meeting about the account.

Practical takeaway: do not buy a performance promise before you can measure performance.

Price the miss before you sign

For this $20,000-a-month account, the retainer’s invoice grows from $12,000 listed to $13,000–$17,000 with illustrated setup. The 15% fee starts at $9,000 and rises with spend. The sprint is one flat fee, paid once, with its stated target and continued work on a miss. All three still need media, and any of them can consume your time or spend money during learning. Keep this hidden-fee rundown beside the proposals, then ask each vendor to price the same 90 days.

Under $10,000 a month, I would look at a small flat fee or a build. At $20,000, I would take the flat-fee sprint with the target defined in writing over a retainer with a setup surprise. Above $40,000, I would not sign an uncapped percentage of spend: the fee rises by arithmetic, not by proof that management got harder. A capped, short-term percentage deal at low spend can behave much like a cheap flat fee. Know which one you are buying.

The cheapest mistake is paying $1,500 for an audit that tells you tracking is broken. The most expensive is paying 15% to scale, then paying full media through every reset while nobody watches change history. Price the miss first.