Costco Bulk Buying vs. Supermarket: When Bigger Isn't Cheaper for Couples

A couple's belief that buying bulk items at Costco saves money may be false if food is wasted, as the effective cost per unit can exceed supermarket prices for smaller packages. In a simulation, a 2-kilogram Costco meat purchase at 3000 yen costs 150 yen per 100 grams, cheaper than a supermarket's 200 yen per 100 grams. However, if the couple discards 30% of the bulk purchase, the actual cost rises to about 214 yen per 100 grams, making the supermarket option more economical. The article highlights that for small households, the key to saving is not just lower unit prices but consuming everything purchased. It cites 2025 household data showing average food spending of 94,895 yen monthly for two-or-more-person households, with a rising Engel coefficient of 28.6%.