It's worth no less than face value and you won't get much more than face value for a well worn note. It's an interesting way to save $50.00 though.
It is likely worth no more than $50 (or a dollar or two over to the right buyer) but various factors can have an impact on value even when the condition is poor. For example, what is the serial number of the note? Also, is it a plain 1934 note or do you see a letter under the year?