What would you price this at?

For every piece of art you use that isn't your own HAS to be credited. It's not your own, and if it isn't credited, then your stealing it. It does NOT matter whether or not your using it for personal art, it is still considered art theft. Just because it's for personal art, does not mean that you don't have to credit. Crediting is always the most important part of art. 

ye I know :3 I still credit, I just don't share it with anybody.