"Artists can pay" is a legal minefield.. lots of potential payola/pay-to-play/bribery issues unless it's made very clear that the artists are paying. Otherwise the more popular you get, the more likely you'll get the FCC crawling down your back.

The music industry is one of the most litigious on the planet.. you have to have balls of steel to play in that fishtank.

http://www.broadcastlawblog.com/2008/09/articles/internet-ra...