What is the value of a 1940 Bank Deutscher Lander Pfennig 50?
The Bank Deutscher Länder (German States Bank) was formed by the western Allies after WW2 so your coin’s date must be 1949 or 1950, not 1940. Look for the mint mark underneath the “50”. If it’s a 1949 coin with a D, F, G, or J it is worth about $2.25 retail. However if it is a 1950 coin with a G, it’s worth about $1,000 and you should have it authenticated by a dealer who specializes in German coins.