Hmm, It looks alright, I wouldn't really know how much it would be worth, maybe some one else can tell you about that. I feel you should add a bit more shading. The shading you have done under the eyes looks a bit too smudged, giving it a really unrealistic look to me. I like the detail you put in with the face but I think you can put a bit more in, just to make it "All that". So right now mate I would give this a 7/10. Good work.