No published CPA rate has been read across the directory yet — that's a gap in what has been checked, not evidence nobody sells it.
See how published rates split out by channel in the buying guides.
CPA (cost per acquisition) is what a buyer pays for each completed outcome an ad produces — a sale, a signup, an install — rather than for exposure or clicks. It is the figure a performance-focused buyer ultimately budgets against, because it is the one unit that prices the result rather than a step on the way to it.
A campaign spends $4,000 and produces 80 conversions. CPA = $4,000 ÷ 80 = $50 per conversion. Whether that is a good result depends entirely on what one conversion is worth to the buyer, which is outside anything a rate card states.
No — a lead (CPL) and a completed sale or install (CPA) are different outcomes, and a seller's rate card should say which one it is pricing. This calculator works the same arithmetic either way; only the label on the outcome changes.
Because it depends on the buyer's own funnel, not just the placement — the same ad spot produces a different CPA for two advertisers with different offers and landing pages. Most sellers publish CPM or CPC instead and leave CPA for the buyer to work out.
CPA = CPC ÷ conversion rate. A $2 CPC placement converting 1 in 40 clicks has a $80 CPA; the same CPC at 1 in 20 halves it to $40 — the conversion rate on the buyer's own site decides which, not anything the seller controls.