At some point you will be confronted with "Pay Per Sale", a payment model for online advertising in which payment is based exclusively on qualified sales!
In a pay-per-sale model, the advertiser only pays for sales generated by the target website, based on an agreed commission rate.
Pay-per-sale is often viewed as the payment model that is cheapest for advertisers and least favorable for publishers. In such an agreement, the publisher needs to be concerned not only with the quality and quantity of their audience, but also with the quality of the creative units and the advertiser's target website.
When possible, many publishers avoid sales-related agreements and prefer to stick to the CPM model . However, some publishers faced with poor ad sales have no choice but to accept sales-based agreements to take advantage of the remaining space.
For advertisers, pay-per-sale offers some unique advantages over pay-per-click and pay-per-lead. There are fewer concerns about whether conversions are legitimate and whether traffic is being promoted or of poor quality.