Check your pockets because your $1 bills may be worth more than you think.
Cool Serial Numbers is a website for those interested in building up their collection of bills with interesting serial numbers. The site looks for bills with eight-digit serial numbers that have interesting patterns.
According to Philly.com, certain patterns can fetch a large sum. Some things to look for include numbers that are all the same, like 55555555; numbers that go up or down, like 23456789; bills with the serial number 00000100 or lower; bills with the serial number 99999900 or higher; palindrome numbers, like 12344321; pairs of numbers that repeat four times, like 89898989; bills with a double quad pattern, like 66663333; and bills with seven numbers the same in a row.
An eBay search reveals that one so-called "fancy bill" is currently selling for $1,000. The bill's serial number is 11223344 and the seller calls it a "perfect ladder in pairs."
Another bill with the number 99999878 is currently on the market for almost $200.
The for sale page on the Cool Serial Numbers website also shows how much people are willing to pay for bills with interesting serial numbers. A $1 bill with the low number of 00000003 is currently being offered for $1,000.
"The prices on my web site are representative of the current market," Dave Undis, the website's owner, told Philly.com in an email.
The website also has a "wanted section" with a list of serial numbers that Undis or other collectors would be willing to pay a hefty sum for. The website notes that they are not interested in coins or any bills that are not U.S. currency.
If you think you have a bill that meets these criteria, you can ask the Cool Serial Numbers to appraise your bill and they can tell you how much you could sell it for.