An auction site called U.S. Currency Auctions estimates that uncirculated $2 bills from 1890 could sell for at least $4,500.

Pull any bill ... it may be worth much more than face value. In fact, collectors are often willing to pay big bucks — hundreds or even thousands of dollars — for rare paper money.

While many of the most valuable coins aren’t in circulation anymore, there are still millions of coins changing hands every day. A Wyoming coin ...