You did not say which model. The Erma-Werke KGP68, which looks like the traditional "Luger" pistol, is about $250-$500, depending on condition. If you have a different model, please repost with that information.
25-160
Impossible to answer without a detailed description of all markings, caliber, finish, etc..
50-500 USD
400
Produced in 1968 with a magaine safety: Exc V.G. Good Fair Poor 500 400 300 200 100
value depends on overall condition
The value of an Erma-Werke handgun actually depends on a number of things. Some of these things include the age and condition of the handgun.
50-200 depending on specifics
25-60 USD or so
What is the value of an ERMA Werke kgp 68 9mm ?
what age serial # 917400