Beginning in 1775, the Continental Congress started issuing Continental currency to finance the revolution; to pay soldiers, purchase equipment, and support other security and governmental actions related to the war. Congress ordered the currency in the amount of 226 million Spanish milled Dollars (which were the common basis of the monetary system at the time). The new currency was not backed by gold or silver but instead by the anticipation of incoming tax revenue.
Counterfeiting was common and resulted in entire series of paper money being pulled from use. The colonies, and Massachusetts was first, also issued their own money to cover war expenses which resulted in further depreciation of the continental currency. 1779 was the final year in which continental currency was produced and, soon after, it took $100 continentals to purchase $1 in gold or silver coins. Some existing currency features punched holes which indicates cancellation.
Image Description: 1776 and 1775 Continental Currency
Image Credit: From the collection of the Groton History Center