CPA (Cost Per Acquisition)
Average cost to acquire one paying customer.
CPA is total ad spend divided by purchases (or signups, depending on the campaign objective). Unlike CPC and CTR, CPA is the metric that ties advertising to business outcome.
Target CPA must be lower than your contribution margin per order. If your AOV is 350 MAD and contribution margin is 35%, your maximum allowable CPA is 122 MAD. Anything above that loses money even before refunds and ad-platform fees.