Every year the phenomenon of beatmaking is becoming more and more saturated with potential beatmakers. This in return has reduced prices and profit for most producers online.
Here are 2 sites that you probably have already heard of if not used at some point of time.
Airbit.com is an MCN (Multi-Channel Network) on Youtube. What's great about Airbit's content id program is that it will collect revenue generated from your beats that is identified in any video uploaded to youtube.
So even if you're just starting out and no one has used any of your beats in there productions you can still make money off of your own uploads to youtube.
With Beatstars.com you can connect your SoundCloud and Audiomack accounts. Beatstar with collect revenue from the streams of your uploads on your profile.
Audiomack will even pay you for streams on other sites that you embed its player.