Getting the best value is frequently an economic mistake for a buyer because it does not take into account the present vs future value of money. Not to mention how it is sure to increase your waste/shrink factor and so can eat up its own savings.

Don’t deliberately overconsume just to feel like a savvy buyer. Buy a reasonable amount for your own needs and no more. I get that we all like Costco, but the business model really isn’t that good for typical consumers.