This article is from the Paper Money Collecting FAQ, by Bruce Giese firstname.lastname@example.org with numerous contributions by others.
During and after the Civil War, the US began to run short on
change, so it printed paper money with denominations of less than
one dollar. These are generally smaller than other paper and are
more affordable than the larger notes of that era. Denominations
are 3, 5, 10, 15, 25, and 50 cents.