Most German .22 revolvers found in the US are inexpensive guns that are no longer imported. If so, probably about $20-$50. But since you didn't give a manufacturer's name or model, it could be something better.
About $25.
25-75 USD
50 or so
Korth
10-100 USD depending on specifics
50-100 or so
Fabico was the US importer of German inexpensive revolvers of indifferent quality, Depending on condition, somewhere around $50
More information is needed to identify the manufacturer of this pistol. No references found.
20-100
100 or so
100-1000 depending on specifics
10-100 usd