Wehrmacht helmet M35 was found at Smolensk region, near village Krasniy Borm. The "Fuhrer headquarters bears cave" was located in this place (Führerhauptquartier Bärenhöhle).
— 10 USD by Russian Post
— 25-40 USD by courier service EMS
— 30-40 USD by Russian Post
— 40-60 USD (depends on customer's country) by courier service EMS
What is the difference between Russian Post and EMS courier service? Read here - link