Hello again, George.
The 5 Reichsmark coin in the picture is in excellent shape and retails well over $500 US dollars. These are valuable coins, with catalog values exceeding $250 even in well worn condition. Since yours has scratches and stains that will knock the value down a bit. If the damage is severe, the value will dip way down.
The 3 Reichsmark coin sells at about half the price of the larger 5 Reichsmark.
DO NOT CLEAN YOUR COIN. CLEANING RUINS VALUE.
Thanks to Munzhandlung Ritter in Dusseldorf for the use of their picture. It sure is a beautiful coin.
The coin commemorates the 450 anniversary of the University at Tubingen.
It is generally a good idea to have any coin worth more than a few $100 authenticated, graded, and encapsulated by a third party service. Use only the following ones: PCGS, ICG, NGC, ANACS. Look them up on the Internet.