I have a $100 bill from 1864. anyone know how much its worth?

Well from the info you gave on here I couldn't say, but you really should take it to a professional in your area. If it's money from the civil war, and in mint condition, it has the potential to be worth thousands of dollars. Just search around on google or yellowpages for coin collectors or something like that. Also if you have any gun shows in your area coming up, there's usually one or two stands at each one. Make sure you don't sell it until you're 100% sure of the price, it would suck to get ripped off for a bad deal.