For the kinds of people who post on HN, the real savings of a Costco membership is that they regularly have high-end electronics, appliances, and home furnishings at $50-100 or more off retail elsewhere. Get a robot vacuum or a couch or a VR headset for $100 off and your membership's already paid for itself that year. For several years, if you need to replace a refrigerator or washing machine.

Paired with a costco credit card it usually pays for itself.