when did the us start using paper money
# The purchase of The US Mint in Philadelphia, was the first money appropriated by Congress for a building to be used for a public purpose. It was purchased for a total of $4,266.67 on July 18, 1792. 1862-1879 â FLOATING fiat currency 7 years. The first use of fiat money (called Greenbacks) in the United States was in 1862, it was used as a tool to pay for the enormous cost of the Civil War. Greenbacks were a debt of the U.S. government, redeemable in gold at a future unspecified date.