Two dollar bills have been issued since 1862. Printing stopped in 1966 due to the unpopularity of the bill. It was brought back in 1976 for the U. S. Bicentennial. Another new series was printed in 1996. The two-dollar bill with Thomas Jefferson and a green seal on front; an engraving of a painting by John Trumball and Declaration of Independence 1776 on the back is a current bill. It is worth $2.00.
There is a perception of the rarity of two-dollar bills. After the Bicentennial printing, people kept them as souvenirs. The collecting craze of the late 20th century encouraged hoarding of the bills as a kind of investment.
Two dollar bills are often used at the horse races because the minimum bet is two dollars.
Valuable two dollar bills feature a red seal and were printed between 1928 - 1966 and are valued between four and twenty dollars.
For more information about paper currency, check out the website of the U.S. Department of Treasury, Bureau of Engraving and Printing.