My uncle found a confederacy $50 bill from 1864 and I want to know the value of it.

I do believe confederate money is not worth the paper it is written on, however, it could be worth nostalgia and you should consult with someone who cn appraise it for you.

My uncle found a confederacy $50 bill from 1864 and i want to know the value of it.
There's no cash value, you can't spend it.
I'd recommend eBay first to see if there's anything to compare it to.
Otherwise you're going to need to find a collector or museum.