One can say that Pay per Click is perhaps the best known Web advertising business model of today, but Pay per Sale could be the Web's advertising business model of the future. Pay per Sale is very related to affiliate selling, but on a wider scale. The most commonly known method of Pay per Sale is of course affiliate selling. The Pay per Sale model can take place with the help of publisher's network or even search engines without the publisher being affiliated to a certain company that is actually selling the product or service. We see strong evidence that advertising and selling products with the Pay per Sale model could become, in the near future, the preferred method of advertising online.