They get money from sponsers. For example the video with Dr.Dre
and Eminem-I need a doctor- You can see the they made money from
the Gatorade that Dr.Dre drinks and the HP laptop that the doctors
have in their hands.
I'd have to say Superman, I mean he might be a fictional
character, but he has been around longer and has made more money
gross and net than Eminem. So Money wise, and length wise, Superman
wins hands down.