People collect old currency! It's only worth as much as someone is willing to pay for it. That particular bill is not all that rare, so I would guess $12 at the most since it is in circulated condition and not graded. The things to look for, especially in older currency is "funny" or low serial numbers i.e. 12344321, 88999988, 00000456 etc.
It may not be worth much, but keep it put up as it will one day, keep it for the kids or something... I have a ton of old currency. I have one coin called a seated liberty quarter from the late 1800's that is worth hundreds due to it's condition, grade and rarity.