British war helmets from WWII are little cheaper than those of WWI according to my research on all completed sales on eBay on the last 90 days. WWII helmets are traded every single day with minimum of 10 bids, which means there are great number of engaged buyers and sellers. You can expect to pay anywhere between $50 - $300 for a helmet based on condition & rarity.
If you are looking to buy a British helmet, you will have to join the bidding war. For example, on September 12, 2010, a WWII British helmet was sold for $267.88 with 24 bids. Take a look at the helmet on the right. It is not in great shape, but still goes for high price because of its rarity.
eBay is indeed the best place for searching WWII British helmets for sale from various sellers and collectors. I don't think there's any other place like it. Below are some of the listing from eBay. Browse the the listing and click on a link which you are interested in. You will be taken to a page with more information on the helmet.
CadRatProductions 1 6 Custom WWII British Canadian Turtle Shell Helmet Set C
Time Remaining: 4h 59m
Buy It Now for only: $5.99
WWII CANADIAN HELMET CL C 1942 SHELL VMC 1941 LINER SIZE 7 3 4 BRITISH
Time Remaining: 2d 14m
Buy It Now for only: $195.00
JAPANESE FIREFIGHTER BADGE JAPAN FIRE CHIEF WW2 FIREMAN VTG TOKYO FD MAYOR HAT
$7.06 (5 Bids)
Time Remaining: 13h 8m
WWII British Safari Tropical Pattern Pith Helmet 1942 Dated Failsworth Hats
$23.00 (3 Bids)
Time Remaining: 2d 6h 7m
WWII British Soldier in Prussian Helmet Keeps Watch on Rhine Orig Press Photo
$4.99 (1 Bid)
Time Remaining: 3d 10h 47m
WWII British Steel Military Helmet Great Condition
Time Remaining: 29d 13h 19m
Buy It Now for only: $70.00
Post WW2 JAPANESE POLICE MERIT BADGE JAPAN CHIEF VTG HAT WAR SET LOT JAPAN PD
$24.50 (4 Bids)
Time Remaining: 5d 12h 58m
1930s JAPANESE FIRE BADGE JAPAN MEDAL CHIEF FIREMAN WW2 HAT IMPERIAL FIGHTER
$7.19 (6 Bids)
Time Remaining: 5d 13h 3m
Here is a list of previously sold British helmets on eBay. Use this as a guide so that you don't pay too much for a helmet in the future.
- Dispatch Rider Helmet 1945 - MINT : $200
- Paratrooper Helmet - REPRODUCTION : $157.50
- Tommy Helmet - 1942 - GOOD : $142.50
- Tommy Helmet - 1942 - GOOD : $79 (notice the difference in price. I checked the auctions and both are almost in same condition. If you shop, you can still buy the helmets for cheap)
- Motorcycle Helmet - 1945 - GOOD : $112.50