Hello, Diana -- This is a Polish coin, but the normal denominations of grosz and zlotych were replaced during the German occupation by fenigow and marka. These coins were minted in iron and carry a small amount of collector value, typically less than $1 US dollar in worn condition. Better condition means better value. Here is a rough accounting:
5, 10, and 20 FENIGOW dated 1917 or 1918:
worn: $1 US dollar approximate catalog value
average circulated: $2
well preserved: $3
fully uncirculated: $5
Two of the coins, the 1917 10 fenigow and the 1917 20 fenigow are more rare, and you can multiply the values above by three to get and idea of catalog value. Don't forget to apply the principles on our Important Terminology page to convert catalog values to actual values.
Now, if you test your coin with a magnet, and it does not stick, that means the coin is made of zinc instead of the usual iron. Zinc fenigows are error coins, and catalog over $50 in average circulated condition.