As a rapper who doesn't want to pay $400 for a beat and you just want to do rap for fun and because you love it, I know what it feels like looking for beats.
Here's where I get all my beats from. They have a wide range of beats to use, all you gotta do is credit them as producer after you DL the free licensed beat.
Passion Hifi
Shadowville
RockItPro
If there are any other sites out there, post them here!