In a very basic sense, affiliate marketing is receiving a commission from a business for "bringing in" a customer, who then makes a purchase. Once that customer has purchased, you are paid for the sale.

Your role is to refer customers to service. When they purchase an account, you get a commission from that business.

Also, you receive a commission from the same account every time that customer pays . So if an affiliate is making steady payments to,  you receive a commission for every payment they make.