I have one dollar bill attached and uncut from another one dollar bill what is it's worth?

Usually just the total face value. You may get a small percentage more if sold to the right person as a novelty item, but a collector wouldn't be interested unless it is very old.

Maybe, maybe notIn the past a misaligned cut was considered to be a major printing error that could sell for $200 or more. Unfortunately scammers have been buying sheets of uncut currency from the BEP and using sharp knives to cut them into fake misalignment errors. It's very difficult to tell a true error from a fake, so the price has dropped a LOT.