This type of programs includes the usual "buy from me and you'll buy cheaper" sites, but having a referal program as well.

This means that if you get pople to subscribe to such a site and after that they will buy something from there, you will get some "points" which you may use to buy stuff from that site.

If you manage to develop a large network of referals that are active buyers on that site you will get enough "points" to buy anything you want from that site.

Go and check the programs in this category...