Hmm...It really depends on the project. The standard cost of a book illustration is anywhere from $500 to $700 depending on the budget,distribution, etc. But since (I'm assuming) you're an independent publisher I'd be willing to negotiate.
it's pretty awesome, I'm impressed on how Baba Yaga is like such an organic figure here, like someone who stayed long enough in the forest, to have things growing on her is just genious, and the way her arms adapted to it also.
I'm (was) a fourth year. Yeah, I don't know what kind of advice to give you. I guess just work on lifedrawing like your life depended on it and work your ass off. Just remember most likely that nothing you do in first, second or third year will make it into your final portfolio, so those years are a great chance to just go nuts and experiment as much as possible. Best of luck to you! Looking at your stuff I'm sure you'll do fine.