If you are just starting out , you first need to understand the options that sponsor programs are offering. Per sign up program pays you a flat rate every time that person sign ups.
All programs claim that they pay per trial membership as well.
Another option is per click. In this case, its very simple, they offer a rate, simply multiply by the number of hits. The only important aspect of this option is to find out if they pay per click on the second page or whatever the case might be. Some programs offer the blind click program and thats a click to front page counted. Third option, and the program used by the most sponsors is partnership program.