Painting Cost?

On my other post of Bumper Help I said that my brother some how put a huge gash on my front bumper and I tryed to buff it out and tryed to cover it up well I colored it with magic marker so my dad dosent see it (he has bad eyesight its just not as noticable.) Well my bumper is the plain gray bumper. Well in two weeks my mom and I are goin to take it in to get fixed how much should it cost to repaint my bumper blue to match the rest of the truck? The bumper is in good shape its not dented it just needs to be sanded and painted. Heres a pic of the bumper before the accident. I just want the metel part painted not the plastic. So please tell me about how much to paint my bumper.