Bid

What is a Bid?

Bid is the amount an advertiser is willing to pay to win an impression in an ad auction. Paid media platforms don't work like TV (rate cards): each impression is auctioned in real time among thousands of advertisers.

The auction algorithm considers three main factors:

1. Bid value (how much you pay)
2. Estimated action rate (how likely the user is to convert)
3. Ad quality and relevance

That's why a very well-made ad can win an auction over a competitor paying more — "quality x bid" wins.

Bidding strategies

Automatic (recommended in 99% of 2026 cases)

• Highest volume: the platform pursues the max conversions for the budget
• Lowest cost (lowest bid): takes what it can at the lowest price
• Cost cap: tries to keep CPA below X
• Minimum ROAS: only spends if projected ROAS >= X (Meta and Google)

Manual

• Bid cap: never pays above X per auction
• Manual CPC bid (Google Ads)

How to choose

• Campaign starting, low data volume: highest volume
• CPA must fit a specific margin: cost cap
• E-commerce with target ROAS: minimum ROAS
• Competitive industry, expensive auctions: bid cap to avoid bleeding
• Awareness/branding: lowest cost

Practical example

B2B SaaS with target CPA of R$ 250 per lead tests strategies:

• Highest volume, R$ 1,000/day budget: 6 leads/day, CPA R$ 167 (great, but low volume)
• Highest volume, R$ 3,000/day budget: 14 leads/day, CPA R$ 214 (scaled)
• Cost cap R$ 220: 11 leads/day, CPA R$ 218 (consistent)
• Bid cap R$ 280: 9 leads/day, CPA R$ 235 (more volatile)

The choice depends on the business criterion. If predictability matters more than raw volume: cost cap. If scale matters: highest volume.

Common mistakes

• Adjusting bids every day (the algorithm needs 7 to 14 days of learning)
• Using manual bidding without understanding the market
• Cost cap too aggressive (algorithm halts delivery)
• Switching strategy mid-flight without resetting the campaign
• Not factoring seasonality into bids (Black Friday inflates everything)