Here’s a look at some of the 12 most valuable American stamps that are still out there, waiting to be discovered by lucky collectors. Learn: 10 Rare Roosevelt Dimes Worth a Lot of Money Also ...

A famous invert error stamp has sold for well over its estimate at a New York sale. Discover the upside-down 1c Pan-American ...

The stamp, seen here with Siegel Auctions President Scott Trepel, once famously featured in an episode of the Simpsons A rare US postage ... of the long-running American animated sitcom The ...