First off all, you need to think quality.
You need to practice and start posting your work in the Art board so people can comment and criticize it. Don't be afraid of some good Cnc and take their advice and try to improve.
You should so this before you try to sell anything, home your skills more and make sure you are up to a certain standard.
As far as how much that head is worth, bluntly, it's worth hardly anything because it's sloppy and you need to practice more.
Take my advice and look at tutorials in Unibash and ask for Critique in the Art board before you start selling.