Do I have to go shopping again? A theory of choice with movement costs

Abstract

In this model, the standard theory of the one-person household is extended into space and time. The theory is extended into space by imposition of a real trip cost on the act of purchase, separate from the money price of commodities. It is extended into time by imposition of a real cost of storage (represented by “deterioration”) on the stocks of goods held in the household between shopping trips. The necessity for storage permits the theory to include an endogenous choice of capacity to store as well as choices among consumption, leisure, and shopping trip frequency. By use of duality theory, the comparative static effects of price, wage, and trip costs are examined. Production and transformation within the household are integrated into the model and shown to be covered by the dual approach.