Costco - should I buy tires there?

[h linamen]

WELL... I finally made my purchase at Sams Club. Only 47 cents more than costco per identical tire and it is local. I would have had to drive approximately 100 miles round-trip for a Costco purchase, along with adding a $50 membership fee. Thanks for all the advice. By the way, I love to get user comments at tirerack.com when researching for tires, but I don't find their prices that much better by the time one pays shipping along with the nuisance of finding and paying an installer.