You've got great skills and should charge accordingly. I know it's hard to try and weigh the price of your work with getting your work out there but it cheapens the skills of yourself and other artists. Your skills and talent are hard earned and don't come over night and people who want quality will pay what you're worth. People who want cheap and quality are usually the ones who are a pain in the behind. If you haven't already you should get yourself on some of the facebook airbrush pages. Your stuff is great and worth more
aaah, this one was for £100 but its like a half of the cost i would like to have, because painting such schemes is not easy, if i get it in hours it might be about 40 for this frame from design to clear finish maybe, then take off about £35 for material, and you have awsome £2/hour for my time, which is less than homelesss income .