What is the central idea of paragraph 3? England also stopped the colonists from making their own coins, so money became scarce. This made it difficult for the colonists to do business. They began to barter for what they needed. The colonists used nails, lumber, farm products, and other things instead of money. They also turned to the wampum that many Native American tribes used for trade. Wampum were beads that were made out of shells.