Mixtape Cover Gig?

Yooooo :)
So like I was asked to do a album cover for this Hip Hop group at my school. And they seem pretty awesome. Its going to be like an inside view of first class seating of a airplane with them doing different things. Wooooo its going to be hard...knowing that this is like my first gig. But how much so I charge them for an Album Cover?

Ill probably post up pics when its done..or its progress :D

xoxo
Jam