These rakeback sites are affiliated with the
poker sites. The rakeback sites make money when you register for a particular
poker site through them. In return, the rakeback sites give you back a % (usually around 30%) of the rake that you pay on the poker site you registered for. I don't know if I should link you to any here, but if you just google "poker rakeback" I'm sure you'll find some. As mentioned, the stipulation is that you generally have to be registering for the poker site for the first time, and use the rakeback site as your referrer (they'll explain what you have to do). Most, if not all, of the rakeback sites won't let you get rakeback if you already have an account at the poker site.