Under the primitive conditions of a barter economy, the services of all persons are exchanged directly, the master rewarding his servant with protection, food and shelter; and, between equals, goods of one kind are exchanged for goods of another kind. The dependence on chance coincidence makes barter an inadequate means of developing a market in which anyone can offer his goods with reasonable assurance of being able to trade for something else at least equal in utility for him.
Except in periods of crisis and confusion (i.e. WWII), barter has nowadays been replaced by money in the exchange of goods and services. Even in the barter arrangements themselves, money is commonly used as the unit of account by which the bartered products are evaluated. The money economy and the free market have replaced the barter economy because barter is burdensome, restrictive, and wasteful.