The people at this store don't seem to know the difference between a retailer discount and a manufacturers coupon. All I can say is that if Autozone is running a special deal, on motor oil in my case, they will not accept your manufacturers coupon on top of it. They don't seem to understand that a manufacturers coupon is not related to any discount Autozone has in place. Instead of processing my coupon, they refused it. It was perfectly valid and unexpired. I ended up going to Walmart to get my oil and filter where my coupon was gladly honored. My purchase ended up being less expensive than Autozone's price anyway. I'm currently considering my options for where to shop next for car parts, and there are a number of good online choices - Amazon and Rock Auto for two.