Autozone, baby, Autozone. Much of my '91 Blazer consisted of parts from Autozone...many with a lifetime warranty...so for years I had free replacement brake pads, water pumps, alternators, starters, ball joints, window motors, spark plug wires...
I have also never felt like I was getting raped for part prices, either at Autozone (as opposed to walking into a GM dealership to get the parts I needed to fix a broken seat rail lock and finding that I would have to pay $250 for a new seat rail, the entire rail...oh, and the cheap plastic lock would eventually break again...well, a $.10 bolt fixed the seat locking issue...course, the seat is fixed in place until you remove the bolt, but it works fine for me)