From my own experience as a collector of coins and paper money, the confederate bills can be worth next to nothing or a lot of money. It depends on their condition and whether they are deemed to be of value because of their rarity and how they were designed artistically.
I would also suggest taking it to a coin shop to determine if it is the real thing or not. There have been a lot of the confederate currency that has been duplicated to look like it is the real thing. If it does turn out to be a genuine Confederate currency, then it would help if someone who knows a lot about them could examine the note in person to determine a condition for it and also its possible monetary value.
You might find the information on the following sites to be helpful to you. I hope that you do.
Quick Reference Guide to U.S. Paper Money Values
A quote from the site above:
Confederate Currency
All genuine Confederate currency has some collector value, although most of the 1864 issue notes are very common (an exception being the $500 note, which is common but popular and is worth from $200 to $400 depending on condition). Earlier issues range from common to rare. All issues from 1861 in Montgomery are very valuable, and we suggest consultation with one of our currency experts if you have such a note. Replicas of Confederate currency are quite common, and are often printed on crisp, brown paper that appears antique. Genuine notes are hand-signed and numbered, and the replicas appear to be hand-signed and numbered as well, although close inspection will easily determine that the signatures on replicas are printed in the same ink as on the rest of the bill. Contemporary counterfeits made to circulate at the time of issue have collector value ranging from $10 to $100 or more depending on condition and the specific circumstances of issue.
The quote below is from the following site:
Confederate States of America Currency - Collection and Sales
Today, the value of these notes is far from worthless. Their prices range from under one hundred dollars for the most common and heavily printed series, to the tens of thousands for the rarest. Most of the heavily printed issues are still available to some extent, while the less common series are getting extremely hard to find. One thing is certain though, all Confederate currency makes as a good investment and has shown to steadily increase in value over the years.