CPA (Cost per Action) — with the help of the CPA metric, advertisers can calculate how much they have paid for targeted action on their site. In other words, CPA is the cost per action.
How to calculate CPA:
This payment for action model is more effective than payment for clicks/impressions from an economics point of view. The CPA metric is the basis of the CPL and CPO indicators.
CPL or cost per lead – this is the cost of obtaining the user's data.
CPO - an indicator of efficiency, this is literally translated as "the cost of the order" and indicates how much the advertiser has paid for selling a unit of goods.
The model is common in Internet marketing because of its simplicity. It is usually easy to track online leads so there is no difficulty in calculating CPA in Internet marketing.
The main advantage of efficiency estimation with the help of CPA is that the expenditure of money occurs only when the user performs the action you need. Thus, you avoid unnecessary spending waste, as, for example, in the case of CPC.