Interstate is just a distributor. Depending on the type, it could be made by any of the 3 major manufacturers and each manufacturer has their own set of lines so you can get good ones or bad ones depending on which line you end up buying.
As for Costco, they have a 100% satisfaction guarantee. There's usually various Costco promos on membership, but you could always buy a membership, then cancel afterwards to get all your money back. Once you have a Costco membership, you could also buy gift cards and that gets you into the store and allows you to buy things without actually being a member. It's somewhat of a pain though because they have to bring some manager over once they realize you don't have a membership card to process the gift card.