The 1939 nickels are fairly common in circulation still. Not worth much more than 5 cents, sorry. Definitely not worth $50.
As furryfrog02 said, a full image of the reverse is needed. With your pic grading is very difficult, but the vertical scratch across the center pretty much kills any value for a normal coin beyond face. All 3 mints used both 1938 reverse dies and 1940 reverse dies to produce 1939 nickels, so you see how important a reverse pic is...Spark
I AGREE pretty common but think you can get .25 cent still fun to find but I am still looking for the big finds