'Straight Outta Compton' Child Actor -- Makin' Bank Like an OG

17-year-old Brockington was guaranteed $6,500 for at least two weeks of work -- according to his contract ... which we've seen. Pretty good payday for a teen actor, especially considering it's his first feature film ... and he'll get to see his name on the big screen.

The take away for JB? Real dollaz ... they eventually multiply too.