Most of us never think twice about a one-dollar bill. It’s the most common note in circulation, exchanged countless times a day. But some $1 bills are anything but ordinary—they can be worth thousands of dollars if you know what to look for.

Collectors pay big money for bills with rare or unusual serial numbers. These numbers, printed in green on the front of every note, can turn an ordinary dollar into a treasure. Some of the most valuable patterns include:

• Low serial numbers – Bills starting with several zeroes (like 00000025).
• High serial numbers – Bills close to the maximum (like 99999999).
• Repeater notes – Patterns that repeat (like 12341234 or 45454545).
• Radar notes – Numbers that read the same backward and forward (like 12344321).
• Solid serial numbers – Every digit the same (like 77777777).
• Binary notes – Made up of only two digits (like 10101010).

What makes these bills so valuable is rarity. While millions of $1 bills are printed, only a tiny fraction carry these unique patterns, and collectors are willing to pay a fortune to get their hands on them.

So next time you’re handed change at the store, take a closer look at your singles. You might be holding a bill that’s worth far more than a dollar.