I sell an old foreign coin

I will sell an old foreign coin, it shows a head in a helmet and the letter is very similar to K on the other side, very similar to N F G, the coin belonged to a German citizen, my husband, for more than 40 years. Selling because my husband passed away. And I know that true connoisseurs of antiquity will be able to save a coin for posterity, not like me, an accidental owner of this value