Description: This song teaches about the history of barter and trading as well as the evolution of the money supply throughout history. This song was voted #41 on the 30th Anniversary DVD Top 46. Economics and the barer system take focus in this episode. A cartoon video carries children back in time, starting with a scene of cavemen trading food and segueing to farmers bartering their farm products in ancientÊMesopotamia. The episode brings the examples full circle as it ends with its characters explaining the origin of paper money and foreign currencies.