I know a lot of guys that run campaigns with MarketLeverage. They are a CPA network much like XY7. You are paid commission based on your sales/leads. There are different types of campaigns you can run so there are different ways you can make money. I am currently working on a post about Affiliate Marketing on my blog.
If you're interested in giving MarketLeverage a try you should also try out XY7 (my referral). The more networks you are a part of the more options you have to work with in the CPA industry