GM parts source

Does anyone know a cheap source for GM parts?
My brother has a GMC Jimmy, he had to replace a few things on it.
Fuel pump - $900
Front wheel bearing - $400 at one place, $290 at another
Upper ball joint - $90
It's a domestic, why are all parts so damn much?!

Do they have to be GM OEM? Ive always had good luck with NAPA, they have excellent quality parts and for sure can beat a dealers price by half most of the time.

PM me if you can make a trip to Burlington and I'll let our pontiac store know that your coming and they can give you a good deal. Something like cost + 20%.