The early American Indians used a barter system to exchange what they had for what they wanted. Barter is a system of exchange in which goods or services are directly exchanged for other goods or services without using money as a medium of exchange. In the case of the early American Indians, they would trade food, tools, weapons, and other items with each other in order to obtain the goods or services they needed. For example, a tribe that had a lot of food might trade some of their food with another tribe that had a lot of tools.