Most businesses start buying ads themselves. Someone on the team opens a Google Ads account, boosts a few Facebook posts, and for a while the numbers look fine. Then spend grows, costs per lead creep up, and nobody can say with confidence which channel is paying for itself. That is usually the point where a company starts looking for a paid ads agency.
A good agency takes over the day-to-day work of running paid media across search, social and display, and it ties that spend back to revenue. A weak one sets up campaigns, sends a monthly PDF full of impressions and clicks, and bills you whether the account makes money or not. This guide covers what the work actually involves, how agencies price it, what to expect in the first 90 days, and the questions that separate the two.
What a paid ads agency actually does
"Paid ads" covers any channel where you pay per impression, click or conversion. In practice most agencies focus on a handful of platforms:
- Search: Google Ads and Microsoft Advertising, including Shopping and Performance Max.
- Paid social: Meta (Facebook and Instagram), TikTok, LinkedIn, Pinterest and Reddit.
- Display and video: the Google Display Network, YouTube, and programmatic buying through a demand-side platform.
- Retail media: Amazon Ads, Walmart Connect and similar marketplaces for product brands.
Across those channels, the core services look similar.
Account structure and setup. Campaigns, ad groups or ad sets, audiences, bidding strategies and budgets. Structure matters more than most people think. An account with 40 overlapping campaigns splits data so thinly that automated bidding never learns anything useful.
Tracking and measurement. Before scaling anything, an agency should confirm that conversions are recorded accurately: purchase events, form fills, calls, and ideally offline conversions from your CRM. If your tracking is shaky, read our conversion tracking guide before you talk to anyone, because every other decision depends on it.
Creative and copy. Ad copy for search, and increasingly the images and short videos that drive paid social performance. Some agencies produce creative in-house; others expect you to supply it. Clarify this early, since creative is often the biggest lever on social platforms.
Ongoing optimization. Search term reviews, negative keywords, bid and budget changes, audience testing, landing page recommendations, and pausing what does not work.
Reporting. A regular view of spend, conversions, cost per acquisition and return on ad spend, broken down by channel and campaign.
The difference between a specialist and a multi-channel paid ads agency is scope. A Google-only shop will usually go deeper on search (see our Google Ads management services guide), while a full paid media agency can shift budget between channels based on where your next dollar performs best. That cross-channel view is the main reason to hire a generalist.
When hiring an agency makes sense
An agency is not always the right answer. It tends to pay off when:
- You spend at least $5,000 to $10,000 a month on ads, or plan to. Below that, management fees eat too large a share of the budget.
- You run, or want to run, more than one platform and nobody in-house has depth in all of them.
- Your cost per acquisition has been rising for several months and you can't explain why.
- You have product-market fit and need to scale spend without watching efficiency collapse.
It makes less sense if you are still testing whether anyone wants the product, if your website converts poorly (ads will only amplify that), or if you have a strong in-house marketer who needs tools and budget more than outside help.
A quick sanity check: run your current numbers through a CAC calculator and compare the result with customer lifetime value from the LTV calculator. If LTV is less than roughly three times CAC, an agency's first job will be fixing unit economics, and you should hire one that talks about that openly.
How paid ads agencies charge
Pricing models vary, and each one creates different incentives. The common structures are below.
Percentage of ad spend
The agency charges a share of monthly media spend, typically 10% to 20%, with lower percentages at higher budgets. It is simple and scales with the workload. The weakness is obvious: the agency earns more when you spend more, whether or not the extra spend is profitable. Many agencies pair this model with a monthly minimum of $1,500 to $3,000.
Flat monthly retainer
A fixed fee, often $2,000 to $10,000 or more per month depending on channels and complexity. Retainers remove the incentive to inflate spend and make budgeting easier. Watch for scope limits, such as a cap on the number of campaigns or creative assets, and for what happens when spend doubles.
Performance-based fees
The agency earns a fee per lead, per sale, or a share of revenue above a baseline. This sounds ideal, but it only works when tracking is airtight and both sides agree on what counts as a conversion. Performance agencies also tend to optimize for the cheapest qualifying action, which is not always the most valuable one.
Hybrid models
A base retainer plus a performance bonus tied to agreed targets, such as CPA or ROAS. This is often the fairest structure for businesses with reliable data, since it covers the agency's fixed costs and rewards results.
Setup and creative fees
Expect a one-time onboarding fee of $1,000 to $5,000 for an audit, tracking fixes and account rebuilds. Creative production is frequently billed separately, especially for video.
Whatever the model, work out the total cost of the relationship as a share of revenue driven. If an agency charges $4,000 a month and the account produces $60,000 in attributable revenue at a 40% gross margin, the fee consumes about 17% of gross profit from paid channels. Our profit margin calculator makes this easy to model before you sign.
Metrics a good agency should report
Clicks, impressions and click-through rate are diagnostics, not outcomes. A good paid ads agency reports on business results first and uses the platform metrics to explain them.
Return on ad spend (ROAS). Revenue divided by ad spend. For ecommerce this is the headline number, but it needs context. A 4x ROAS is excellent for a 70% margin product and loss-making for a 20% margin one. Calculate your break-even point with the ROAS calculator so you know what target actually means profit.
Cost per acquisition (CPA). What you pay for each customer or lead. For lead generation, insist on cost per qualified lead or cost per opportunity, not raw form fills.
Conversion rate. The share of clicks that convert. A sudden drop usually points to landing page or tracking problems, not the ads. The conversion rate calculator helps you benchmark this by channel.
Blended metrics. Platform dashboards each claim credit for the same sale. A mature agency reports blended CAC or marketing efficiency ratio (total revenue divided by total ad spend) alongside platform numbers. If attribution is a sore point, our guide to marketing attribution software covers the tools that reconcile these views.
Incrementality. The best agencies will at least discuss whether ads are driving sales that would not have happened anyway, especially for branded search and retargeting, and will run holdout or geo tests when budgets allow.
What the first 90 days should look like
A structured onboarding tells you a lot about an agency. Roughly, expect:
Weeks 1 to 2: audit and access. The agency reviews account history, tracking, audiences, creative and landing pages. You should receive a written audit with specific findings, not a generic checklist.
Weeks 2 to 4: fixes and restructure. Tracking gets repaired, wasted spend is cut (irrelevant search terms, poor placements, overlapping audiences) and campaign structure is consolidated. Performance can dip briefly while automated bidding relearns.
Months 2 to 3: testing and scaling. New creative, audiences, offers and channels are tested in a controlled way. Budget moves toward what works.
By day 90 you should see clear improvement in at least one efficiency metric, or a well-reasoned explanation of what the data shows and what comes next. Be wary of any agency that promises doubled ROAS in the first month. Quick wins are usually waste reduction, and those are real but finite.
How to vet a paid ads agency
These questions filter out most weak agencies quickly.
Who will actually manage my account? Many agencies sell with senior staff and hand the work to junior specialists juggling 20 or more clients. Ask for the account manager's name, experience and client load.
Do I own the ad accounts and data? You should. Accounts should be created under your business and shared with the agency as a manager. If an agency builds everything inside its own accounts, you lose the history when you leave.
How do you measure success, and against what baseline? Good answers mention your margins, LTV and business goals. Weak answers focus on clicks and CTR.
Can you show case studies in my vertical and spend range? An agency that runs $500,000 a month for enterprise brands may not prioritize a $15,000 account, and vice versa.
What is your creative process? On Meta and TikTok especially, creative volume and testing speed drive results. Ask how many new ads they typically launch per month.
What are the contract terms? Month-to-month or a short initial term (three months) with a 30-day notice period is reasonable. Twelve-month lock-ins with no performance exit are a red flag.
How often will we talk, and what's in the report? A monthly report plus a regular call is standard. Ask to see a sample report with client details removed.
Other warning signs: guaranteed rankings or results, reluctance to give you admin access, reports built only on platform-attributed conversions, and pressure to increase budget before tracking has been validated.
Agency vs. in-house vs. freelancer
Each option has a place.
An agency brings a team with specialists across channels, tools and benchmark data from many accounts. You pay for breadth and continuity. The trade-off is less direct control and shared attention.
An in-house hire knows your business deeply and works only on your account. A strong senior paid media manager in the US typically costs $90,000 to $140,000 a year plus benefits, and one person rarely has expert depth on every platform.
A freelancer can be excellent value for a single channel at modest budgets, but capacity and cover for holidays or illness are limited.
Many growing companies end up with a hybrid: an in-house marketing lead who owns strategy and budget, with an agency handling execution on the channels where specialist depth matters most. For ecommerce brands specifically, our guide to PPC for ecommerce goes deeper on how Shopping and Performance Max fit into that mix.
Getting the most out of the relationship
Agencies do their best work when clients do a few things well:
- Share real business data. Margins, LTV, sales cycle length and which leads actually close. Without it, the agency optimizes for proxies.
- Give feedback on lead quality quickly. For B2B and service businesses, a weekly note on which leads were good closes the loop faster than any tracking setup.
- Keep landing pages moving. Ads can only send traffic. If the page doesn't convert, budget increases just buy more bounces.
- Agree on a testing budget. Setting aside 10% to 20% of spend for experiments keeps the account from stagnating.
- Review the numbers against your own books. Compare agency-reported revenue with actual revenue each month. Gaps are normal; large or growing gaps need explaining.
Frequently asked questions
How much does a paid ads agency cost? Most charge 10% to 20% of monthly ad spend, a flat retainer from about $2,000 to $10,000 a month, or a hybrid of retainer and performance bonus. Onboarding and creative production are often billed separately. Minimum monthly fees of $1,500 to $3,000 are common.
What is the minimum ad budget worth hiring an agency for? Around $5,000 a month in media spend is a practical floor. Below that, management fees take too large a share and there is not enough data for meaningful testing. Smaller budgets are often better served by a freelancer or a focused single-channel setup.
How long before a paid ads agency shows results? Waste reduction and tracking fixes usually show up in the first four to six weeks. Sustained gains from new creative, audiences and channel mix typically take 60 to 90 days, longer for B2B products with long sales cycles.
Should I hire a specialist or a full-service paid ads agency? If one channel drives most of your revenue, a specialist in that platform usually goes deeper. If you run three or more paid channels and want budget to move toward the best performer, a multi-channel agency with a unified reporting view is the stronger choice.