This is one reason why I seldom do commercial jobs. I don't have the patience or the business skills to manage the whole pricing/negotiating thing. And it's why I have a day job, to keep me in the toys to which I have become desirous of.
I learned that the hard way. That's why I have a day job now. I wrecked a hobby, got burned out and didn't pick up a camera for years. I'm doing for the love of it now. It's so much better