It costs $25 bucks to join ASCAP--one time fee. You can do it online--the amount of money that you make depends on how many songs you have out there, and how much they get played.   I used to have all the numbers, but times have changed--I do know that the songwriter cut of a music download is about 9 cents (and also that Apple and the RIAA, have asked for that to be cut). If someone has a triple platinum album, with ten songs on it, it could be pretty good.