After the war, the United States had a booming economy. Unemployment was low, and Americans secured loans to purchase new consumer goods such as cars and radios. In Europe, however, the war had taken its toll.
In the United States the economy was very good throughout most of the 1920s (it was often referred to as the "roaring 20s" for this reason). However much of this prosperity proved to be built on a flawed economic foundation, which helped lead to the Great Depression.
The increase of trade led to a new kind of economy. During the middle ages people traded goods for other goods. During the Renaissance people began using coins to buy goods which created a money economy.