Pull any bill out of your wallet. See the dark green numbers on the top-left and top-right corners? Those are serial numbers, and some are more rare than others. If you happen to have paper money with ...

A widely circulated article claimed paper money would be swapped for "TrumpCoin" and a line of gold coins embossed with the president's likeness.

Paper currency doesn’t get as much attention on the collector’s market as coins, which have a metal content that boosts their value and sometimes date back to the earliest days of human civilization.