Here, Kilgore recommends six items that retirees — and the rest of us — should never put in their grocery carts to save and spend smartly. Bulk buying — whether at membership warehouses or the local supermarket — only saves you money if you buy products you’ll consume quickly or items you frequently use. Aaron Cirksena, CEO and Founder of MDRN Capital, a retirement planning services firm, said bulk buying becomes expensive for retirees when they purchase large amounts of perishable goods like meat, vegetables and fruit that go bad quickly.