Agreement

If a buyer and a seller agree on the purchase of a good or service, it is called a contract. A contract can exist in text. But what you decide when talking to each other can also be a contract. You must be 18 years old for a contract to be valid, unless a parent or other guardian approves the purchase. However, if you are 16 years old and buy something with money you have earned yourself, the contract can also be valid.