Collectors will pay a premium for unique coins or rare bank notes. So, if you've got any $1 dollar bills lying around, you may want to examine them closely before spending them as they could be worth thousands.

Ordinarily, dollar bills each have their own individual serial numbers. However, in 2014, the Bureau of Engraving and Printing made a rare printing error that resulted in millions of $1 bills with duplicate serial numbers entering into circulation, according to PMG, the world's largest third-party paper money grading service.

Although these special pairs of $1 bills with matching serial numbers were initially printed in Washington, D.C., and Fort Worth, Texas, they could be anywhere in the world after a little more than 10 years in circulation.

It's important to note that the misprint doesn't make these $1 bills unusable, and they're probably not worth more than a dollar on their own. However, if you manage to find a matching pair, you could earn thousands from collectors.

A pair of $1 bills with duplicated serial numbers sold for $2,340 at an auction held by Stack's Bowers in March. Another pair sold for $7,200 at a Stack's Bowers auction in 2021.

Here's what to look for.

How to check if your $1 bill may be worth thousands

First, you'll want to locate the Series date, which is found near the picture of George Washington. It must read "Series 2013," per WealthyNickel.com.

Then, make sure the bill has a "B" Federal Reserve Seal above the serial number.

Finally, check that the serial number ends with a star and falls between B00000001* to B00250000* or B03200001* to B09600000*.

There are a little more than six million of these misprinted $1 bills in circulation, according to WealthyNickel.com. However, there are more than 14 billion $1 bills circulating as of Dec. 31, 2022, per the Federal Reserve's latest data available.

Remember, although you may have a single $1 bill with these features, the key is to find its match. One way to do this is by checking Project 2013B, which maintains a database of these unique banknotes. The project reported making its 16th match of 2024 in April and says more than 100 pairs have been matched already.

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