A Costco Gold Star membership costs $65 a year - which means it pays for itself the moment you've saved $5.42 a month. For families, that's almost effortless: gas savings at Costco's pumps alone typically cover the annual fee several times over, before a single warehouse item goes in the cart. But households that have shrunk — empty nesters, singles, newly divorced - sometimes find the calculus has changed. Buying a three-pound bag of spinach for two people rarely ends well. The smarter move for smaller households: focus on non-perishables, pharmacy, and gas, where bulk buying still makes sense regardless of family size. And every Gold Star membership includes a free Household Card - meaning you can split bulk purchases with a friend and both come out ahead.