I'm on my third set of tires from Costco in the last year and a half, on 3 vehicles. It's a great place to buy tires, I ordered them online, and saved me about 6% in excise tax. They fixed a flat for free, no waiting and told me about a bent rim I had.
Got new rim, they remounted the tire on for free, and disposed of the bent rim. They use nitrogen, and I told them I inflated with air at one time. They bled the air out of all fours, and refilled with nitrogen for free. Lifetime balancing, and rotation, and road hazard for free. And on top of that the occasional $20 per tire discount. Hard to beat Michelins, and the fairly inexpensive BF Goodrich, if you are going that route.
Get the executive membership, and get 1% off, or is it 2% all your purchases, except gas. Will pay for itself in a year.