The helmet was restored from the original German helmet during the second World War using the method of artificial aging. Liner is a reproduction. In the last photo You can see how the helmet looked before the restoration
— 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