You have, as best I can tell, Akit, a gold-plated brass alloy coin minted in Germany during the highly troubled times after World War I and before World War II. Its denomination is 'not goldmark' which means 'emergency coin equivalent in value to one gold mark' and it is part of a large group of similar coins known as 'notgeld' or 'emergency money.' We have a CoinQuest page that addresses these coins at this link.
This piece was minted by the independent city of Bielefeld ('Stadt Bielefeld') in north-central Germany. The picture is from one of our favorite coin collector sites, ForumAncientCoins.com, and CoinQuest thanks The Forum for use of the image. It is a beautiful piece and the Forum's write-up by Jochen gives tons of details about it.
As to value, it is difficult to pinpoint a price on such an elegant piece with potentially strong emotional ties. Typical values for this piece run:
worn: $5 US dollars approximate catalog value
average circulated: $10
well preserved: $25
fully uncirculated: $75
These are catalog values. Refer to our Terminology page for an explanation about how catalog values work.