Prices around here for blasting AND powder coating run $20-40 per rim, that's a super deal in my mind. You personally don't have to mess with blasting or paint, and have a better end product. I had my wheels powder coated, I think it was $30 each, and it is tougher than paint.
To avoid scratching the rims when you install the tires do it by hand, don't use a tire machine unless they guy running it is sure he won't scratch them...
Grigg