Media Buying
Media buying is the purchase of advertising inventory across digital and traditional channels to reach a defined audience at a workable cost. In digital, buying happens through self-serve platforms such as Google Ads, Meta, TikTok, and LinkedIn, or programmatically through demand-side platforms such as The Trade Desk. The buyer sets budgets, bids, targeting, and pacing, then adjusts based on performance. Media buying covers the commercial decision of what to buy and the operational work of paying for it.
Last updated: August 2026
Why media buying matters
Media buying is where most performance marketing budgets are actually spent, which makes it the point where finance and marketing collide.
The buying decision is a marketing one. Funding it is a finance one, and the two run on different clocks. Platforms charge continuously, in threshold increments or on a monthly invoice. Clients pay on terms. An agency sitting between those two schedules is carrying the gap, and the size of that gap is set by how the spend is funded rather than by how well the campaigns perform.
How businesses approach media buying
- In-house teams buy directly for their own brand and answer to an internal budget.
- Agencies buy on behalf of clients, which introduces client funds, approvals, and reporting.
- Programmatic buyers purchase inventory through auctions rather than platform interfaces.
- Hybrid setups keep brand campaigns in-house and hand performance channels to a specialist.
Business examples
An agency running $400,000 a month across Meta and Google for eight clients. A DTC brand buying TikTok inventory in-house. A performance team using The Trade Desk to buy programmatic display alongside paid social.
Frequently asked questions
Planning decides which channels and audiences to use and how much to allocate. Buying executes that plan: setting up the campaigns, placing the spend, and managing pacing. In smaller teams the same person does both.
Through a payment method stored in the ad platform, most often a business card. High-volume advertisers are increasingly moved to monthly invoicing paid by bank transfer, which removes card rewards and changes the cash flow shape of the spend.
Enough headroom above peak monthly spend that a strong month does not hit the ceiling. Traditional business cards size limits on the agency's own financials, which understates what an agency managing client budgets actually needs. Opal sizes limits on managed ad spend and cash flow, with limits up to $10M.
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