Good info on that peice of history
In the Summer of 1862, the Union position in the Civil War was becoming increasingly uncertain, and in the South, the citizens of the Confederacy were experiencing shortages and problems.Coins had been hoarded since late in 1861 and by late 1862, not even copper-nickel
Indian cents were anywhere to be seen.It was impossible to find a coin, with which to pay for a newspaper, get a haircut or take a ride.
On July 9th 1862, Horace Greeley, owner of the New York Tribune, suggested that postage stamps, could be used as change by the nations merchants.The idea was a good one and caught on quickly prompting the Treasury Department on July 14th, to send a memorandum to Congress, petitioning the use of postage stamps as legal tender. In response, an act of government was passed on July 17th 1862, that 'provided for the use of postage stamps for monetary transactions'.
In August of 1862 the postage currency idea was pursued, further, and refined. Fractional Bills were issued featuring similar designs as stamps, but in the shape of small pieces of paper money.At first these were dstributed to Army paymasters, but by September were in general use, by the public.
During the following war years and beyond, a total of five 'series' of Fractional Currency were introduced, and today collectors are investing in 3c, 5c, 10c, 15c, 25c and 50c fractionals, with an ever increasing hunger.