When we speak of the economy of a country, we mean the system which that country uses to produce, distribute, and consume goods. The economy of Babylonia was based, like that of Sumer, on agriculture. In Sumer, agricultural products such as grain and wool were often traded for goods the Sumerians could not produce themselves. Exchanging goods (or services) for other goods or services without using money is known as bartering.

Bartering was used in Babylonia, too, but money gradually replaced it as a means of exchange. The money was in the form of bars of precious metals—silver, copper, or gold. The Babylonians even had banks to manage their money. Money had many advantages. For example, it is easier to handle and exchange than grain.

Try to think of some other advantages that a money-based economy might offer over a bartering system. 

Above is a depiction of Babylonian gods and a goddess involved in what appears to be a ceremonial exchange. 

Picture from http://www.mesopotamia.co.uk/gods/explore/main.html