Why would an artist have to pay for a gig or preformance?

A buddy of mine hasn't been in the rap game too long, and he's got an upcoming show this weekend competing against 14 other artists in front of A&R Management Artist Showcase for Def Jam, Grand Hustle, A&R Management. He got a flyer that was posted up for it at a big rap concert a week ago. Anyways, he showed me the ticket and he had to pay a bunch of money it looked like on the receipt copy they sent him through his email. Why would an artist have to pay for a preformance? There is a seminar where A&R management is going to like talk to the artists about how they go about branding themselves in the industry and than the rapping showcase starts later on that night and the winner gets 500 dollars, free studio time, 1000 cds pressed and distributed in ATL. I know there are scams out there but this seems legit, and the bar its being held at is a real place but doesn't seem like a venue that would host this pretty big event. I just don't want to argue with my buddy because i know there are scams out there, its just that I don't see why he would have to pay a bunch of money to preform (I think it was around $150)? He had to call the number to reserve a slot. He did have to pay in the past like 15 bucks to preform for a small label that was hosting a concert, and he did that successfully, but that was only $15. Don't know to much about booking preformances in the industry for young artists.