Pay per Action (PPA) is a payment model in online advertising. Pay per Action (PPA), often referred to as Cost per Action
(CPA), is a very efficient payment model for advertising buying companies. In Pay per Action, the advertising company pays only for a specific action by consumers based on the online advertising medium. Such a specific action by consumers is, for example, a completed online form with relevant data
or a completed purchase, as in pay per purchase. The pricing model is very efficient as it is mostly self-financing in the case of Pay per Purchase. Besides Pay per Action (PPA), there are several other payment models for online advertising. For example, Pay per Click (PPC), Pay per Impression (PPI), Pay per Lead (PPL) or Pay per Sale (PPS).