How much is the cost to get a scar covered by tissue expansion? (Photo)

I am 36 years old, 30 years ago I had a car accident and a little scalp was removed from my head. My hair never grew there. I always had had to cover that space with the rest of my hair. This has always made me feel uncomfortable and embarrassed. So I decided to get a surgery but I do not have insurance. I will pay by myself and I need to know which is the approximate cost. Thanks