How to Start a Marketing Agency Business
From the services you'll sell to the first monthly retainer a client pays, in the sequence an agency launch follows.
Starting an agency means choosing the services you'll sell and who you'll sell them to, then setting up the structure, tax ID, bank account, insurance and contracts before the first client signs. Retainer pricing and invoicing are explained elsewhere on Billed (How to Invoice as a Marketing Agency); this page is about launching.
On the work itself, the BLS occupation profile for advertising, promotions, and marketing managers (In the US, BLS, last modified August 27, 2026) says "Advertising, promotions, and marketing managers plan programs to generate interest in products or services." On background, it says "Advertising, promotions, and marketing managers typically need a bachelor’s degree. They also typically need work experience in a related occupation."
Worked sample for the first bill: a monthly retainer at 1 × $1,800.00 and 4 hours of ad account setup at 4 × $85.00 = $340.00 come to $1,800.00 + $340.00 = $2,140.00. Use your own figures; these are only an illustration.
Step-by-step startup guide
Follow these steps to launch your marketing agency business on solid footing.
- 1
Pick your services and clients
Decide which services you'll sell at the start, such as social media, paid ads, email or content, and which kinds of clients you'll serve.
- 2
Choose a structure and register
The SBA (In the US, SBA, checked October 31, 2026) says "How and where you need to register depends on your business structure and business location."
- 3
Get an EIN before you hire
The SBA (In the US, SBA, checked October 31, 2026) says "Your Employer Identification Number (EIN) is your business’s federal tax ID number. You need it to pay federal taxes, hire employees, open a bank account, and apply for business licenses and permits."
- 4
Put each engagement in a contract
Write down the services, deliverables, reporting, the monthly fee and how extra work is billed, and ask a lawyer to review your standard contract.
- 5
Insure the agency
The SBA (In the US, SBA, checked October 31, 2026) says "You also may be legally required to purchase certain types of business insurance." An insurance agent can compare policies for agency work.
- 6
Track time from the first project
Have everyone log hours against the client and task from day one, so retainer reports and extra-work invoices come from the same records.
Tips for starting your marketing agency business
- Work out your estimated tax early. The IRS (In the US, IRS, last reviewed or updated September 25, 2026) says "Individuals, including sole proprietors, partners, and S corporation shareholders, generally use Form 1040-ES, to figure estimated tax."
- Decide before the first campaign how ad spend you place for a client is paid, and show it on its own line of the invoice.
- Keep a log of the client's approval for each piece of work you publish for them.
- Send the monthly report in the same format each time, so the retainer invoice and the report line up.
How Billed helps you get started
Features to look at as you set up your business.
Recurring Invoices
Billed's features page lists "Recurring Invoices": "Save time by sending invoices on a regular schedule so you don’t have to create invoices again and again."
Team Time Tracking
Billed's features page lists "Team Time Tracking": "Say goodbye to spreadsheets. Collaborate and track your team’s time in one place."
Flat Rate Projects
Billed's features page lists "Flat Rate Projects": "Manage your flat rate projects and create Invoice at any stage of the project."
Project Invoices
Billed's features page lists "Project Invoices": "Keep all invoices related to your project in one place."
Frequently asked questions
Invoice Your First Retainer
Create invoices, track payments and keep your clients' details in one place with Billed.
At a glance
| Stage | What to check | Source |
|---|---|---|
| Registration | Where and how to register | SBA (In the US, SBA, checked October 31, 2026) |
| Tax ID | An EIN before you hire | SBA (In the US, SBA, checked October 31, 2026) |
| Contracts | Services, reporting, fee, extra work | Your own contract, reviewed by a lawyer |
| First invoice | Retainer plus any extra hours | Marketing agency invoicing guide |
When this isn't for you
Hired into an agency or an in-house marketing team? This launch checklist isn't for you; the business you join runs the contracts, insurance and billing.