my avatar contains wheels i have painted black myself.
took me a good 2 days, that was cleaning, sanding, puttying all the gutter rash, sanding again, sanding again.... and again. primer. black spray then gloss spray.
tyres were still on wheels, just masked up. all up cost me like 50ish dollar in paints and stuff. then a bit for sandpaper and tape. definatly less than $100.
poweder coating in the end would probably be better, but would cost anywhere from $150 - $400
my coats still holding up fine also after 3 months