CPA or cost per action marketing is a pricing model used in mobile user acquisition campaigns in which advertisers choose a post-install action to measure, and only pay for users who engage in that action. That means in order for advertisers to pay, the user must see their in-app ad, install their app, and complete the action.
In CPA advertising, advertisers set the action to whatever they’d like, for example: signing up for a free trial, registering for a free download, buying a product, etc.
The cost per action formula is calculated by dividing the advertising cost by the number of times the action occurred.
CPA = advertising cost / number of actions