does anyone know where to go to find out the value of a silver dollar paper bill dated 1938-1940?

Answer 1

Since all US silver certificates of this era were Series 1935/1935A, then if you have a US banknote dated 1938 - 1940, it's a fake, Jake.
I think you need to supply a better description of what you are looking for here. If you want to know about Series 1935 silver certificates, go to eBay, category US coins > US paper money and do a search for "1935". You will get a listing of all such notes presently for sale, which will give you a very specific idea of value.

Answer 2

try this site
http://uscurrencyauctions.com/$1notes.htm

Answer 3

pcgs.com