Not as useful as the marching boot. Any basic grey wool sock will do. The German ones have size rings in white at the top. No pockets, buttons down about half way. Light cotton shirt with pressed paper buttons, pleated pockets and tabs for the shoulder boards.
Originals are common and very useful.
Please consult with unit commander to assist in putting together your impression. A large number of weapons were utilized for Volkssturm use, many were obsolete or captured weapons from earlier campaigns from the Glory days of the Wehrmacht. Italian Carcano Bolt Action Rifle and Carbine. There may be others but the above were the most common, discuss with unit commander which weapon you desire to use with your impression before purchasing or bringing your weapon for an event, especially those that are not on the list - so that you get what you need the first time correctly. Usually restricted to NCOs and Officers.