The money you have in your wallet could be worth more than you think, just because it might have slight imperfections. You can find all kinds of mistakes. Mistakes are called errors in the collector's world. They are bills and coins that have slipped past the scrutinizing eyes at the U.S. mints. Billions of dollars in redesigned U.S. currency has opened the door to money errors.
Coins are also flawed.
Collectors are intrigued with mistakes as well as oddities known as fancy money. These involved serial numbers on the bills. The repeater is a series of numbers that repeat, such as 0111 and 0111. A tiny red star at the end of the serial number means that it is a replacement note and worth more than the face value. Finally, the gutter notes are imprinted creases or folds that are very popular with collectors.