Why Do I Need To Use Coupons at CostCo?

My wife raised a really good point as we were driving home from a successful, albeit annoying, trip to CostCo. Why do we need to have coupons to get deals on stuff that's on sale?

We pay for a membership, why should we have to clip coupons to get the deals as well? That just seems unnecessarily stupid and an extra step.

CostCo would be much better served by just putting a sale tag on the item and letting everyone who wants to buy it, buy it at the sale price. As it is, we were annoyed because they gave us the coupons on our way out, the coupons expired the next day and we could have and should have saved a small chunk off our bill. But now we have to remember to take the coupon and the reciept back in with us to get the damned money.

CostCo should be working for its members, not making them work harder to get a few extra bucks off their bills. I think I'll drop a short note to CostCo to let them know that.