Cost per action advertising often called CPA is a model where affiliates earn money only when a visitor completes a specific action requested by the advertiser. The action might be filling a form installing an app starting a free trial or making a purchase. Affiliates usually buy traffic through ads and send visitors to a landing page or directly to the offer link. When the visitor finishes the required step the network records it and pays the affiliate a fixed commission. Profit comes when earnings are higher than ad spending. What is the general opinion about the CPA payment model in affiliate marketing?