Two dollar bills are often considered a rarity, but just how rare are they? Here's how much a valuable bill could be worth.

A longtime bank teller said nothing can slow down her day more than a customer asking for a $2 bill. "Seriously, you don't want to be that person," she said.

Red or brown seals on older $2 bills—especially pre-1963 or WWII-era notes—indicate rarity and higher collector value, especially if pristine. Parkinson’s Isn’t Just Bad Luck. Scientists Reveal It’s ...