> Costco is for bulk staples and commodities for me

> Milk, eggs, flour, flowers, microfiber towels, batteries, salt and pepper

If you can walk out of Costco month after month with just those essentials, and never pick up any of the nice-looking and reasonably-priced goodies there, I think it's safe to say that you have the level of discipline required to be financially successful and not have to care about whether you're getting the best price per unit of whatever it is you're buying. :-)