How much should I charge for graphic design work?

[Michaela]

I'm a graphic design student, and a kid I know who is trying to become a rapper (I mean he gets gigs and he's pretty good I suppose) had told one of my good friends he's looking for someone to do some designs for him and she mentioned that I'm studying in that. He told her to let me know and contact him and he'll pay me. Incase he asks how much do I charge.... I have no clue. I've never done work for anyone, so I'm asking for maybe some examples? I'll probably be doing like logo and maybe a FB Timeline cover and maybe posters or cd cover or something? I've done all that stuff for internships but I would have no clue how much to "charge" someone. I don't want to say a lot of money, but I don't wanna do super cheap either, a profit would be nice.

So confusing but thank you!