Cost Per Action is an online advertising method where an advertiser pays each specified action like as an impression, click and form submit.CPA is considered many optimal ways to get advertising for the offers that you wish to offers. Using CPA for an offer will almost always make sure that affiliates will want to promote the offer providing that the CPA is worth it for them.
An advertiser pays $50 per action
The publisher will promote their CPA link which will have a unique ID for them.
When customer clicks on the link and then purchases the product, the CPA payout $50 credited into your account.
In the CPA advertising model, the publisher takes risk as income is dependent on good conversion rates. Because of this, selling on a CPA basis is not as desirable as selling ads on CPM basis. Some publishers who have surplus inventory will often fill it with CPA ads. The effectiveness of advertising inventory purchased by an advertiser can be measured using effective cost per action. A CPA deal could include any action, not just a customer sale. When the action is click, the sale method is referred to as CPC a.
In those days many online shopping websites are using CPA programs (affiliate programs) and many publishers make huge money using affiliate programs.