Not all old coins or dollar bills are unique, but some could be worth thousands of dollars. And if you do have old currency lying around, it doesn’t hurt to check and see what it’s worth.

You can call it a C-note, a Benjamin, a Franklin, or a Ben, but no matter what nickname you give it, a 100-dollar bill is always worth at least $100. In some cases, though, super rare 100-dollar ...

Learning to spot the most valuable 10-dollar bills means knowing what makes them worth so much. We're talking super old currency, special serial numbers, interesting mistakes in printing ...