Another major role of marketing relates to change in ownership. Agricultural goods, like most other goods, have value only in terms of their usefulness -- utility -- to consumers. The pricing and exchange functions associated with possession are the heart of marketing. Pricing is the determination of market values in terms of money. Buyers and sellers at a given time agree on a common evaluation. Prices may vary from day to day or hour to hour, depending on demand and supply. But, in time, prices of different commodities seek different levels in accordance with.