Well, a MAACO job will run $300 and up, a decent paint job will run $2000 and up.
I can't see $2000 worth of materials, but $500 for materials is a better ballpark figure, still not cheap.
My corvette restorer friends tell me you can't get a decent paint job for $10,000!
I have painted two cars and a cousin painted one, all three in garages or barns. We weren't pros, and it showed. HELLO, ORANGE PEEL!
We had decent equipment, guns were Binks, for example, but clearly didn't know how to apply a coating. It took me a month to cut down most of the excessive bumpiness on one car, one car went to its grave with considerable orange peel.
So, I say it may seem easy but it's not. It's an art. And the prep is labor-intensive with no real way of making it easier.

In the long run, you get what you pay for. If your cousin wants a custom job, I guess he'll end up with about $3000 in it. Is it worth that to him?
R.