Money is pretty old but nobody knows exactly how old it is. Perhaps the oldest evidence of people using money is in the Code of Ur-Nammu. The Code of Ur-Nammu is a system of laws written around 2050 BC. That's like 4,000 years ago! Many of Ur-Nammu's laws carry fines, such as one stating that if a man is proven innocent of sorcery, his accuser must pay 3 shekels. This ancient document shows me two things: Ur-Nammu didn't tolerate false witch-hunts, and money is very old.