A one-dollar coin is a type of currency that is worth one United States dollar. It is made of metal and is typically round in shape. The U.S. Mint has produced several designs of the one-dollar coin, including the Susan B. Anthony coin and the Sacagawea coin, which features a Native American woman. These coins are used in everyday transactions, although they are less common than paper dollar bills. The one-dollar coin is often collected by numismatists and can be found in circulation, but many people prefer to use bills instead.