Almost every society eventually created its own form of currency. Currency is anything that people agree to take in exchange for goods, like food, or services. Throughout history, people have used many different things as currency: seashells, cows, animal teeth, even salt.

People have chosen their currency because it's useful, like grains or spices; or because it's pretty, like seashells or jewels; or because it is hard to get, like sharks' teeth.

To do business with each other, communities had to decide how much their currency was worth compared to someone else's currency. When settlers first came to Massachusetts, the native Americans used a currency called wampum, made of seashells strung together. Dutch settlers bought the island of Manhattan from native Americans for strings of wampum that were worth about sixteen dollars in Dutch money.