The purchase of shoes which reduces expected medical expenses associated with improper footwear may well be "something that puts money in your pocket", provided

The purchase of shoes which reduces expected medical expenses associated with improper footwear may well be "something that puts money in your pocket", provided the expected savings outweigh the marginal opportunity cost of the shoes. A durable good which you own in order to make yourself more productive is known as a capital good. Shoes, clothes, and shelter qualify, to the extent that having these things increases productivity. Food would not qualify, since it a consumable and not a durable good. The purchase of capital goods, for the purpose of increasing productivity, is investment.