All rappers, popstars, etc are just in it for the money and fame. One example: Puff Daddy or whatever his name is. Changed it just so he could get attention.
Most rock "stars" are in it because they love the music, and that's all there is to it. They could care less about the money. Afterall, you don't see them walking around in bling-bling, do ya? Unless you count Joel Madden, who is now Hiliary Duff's freaking minion