That's a very nice collection but its unfortunate that this is the only picture available. Nevertheless, I'll do my best to identify the helmets but I am sure that other collectors who are much more knowledgeable have more to add. The first one represents possibly an older (pre 1895) Prussian Mannschaften pickelhaube. The second one is a garde officer's pickelhaube, but I am not sure whether this concerns also an older helmet type because this helmet is hidden in the back of the pic. The third one is a Bavarian officer's infantry pickelhaube and the fourth one is a Bavarian reserve artillery Mannschaften Pickelhaube (M1895). The fifth one comprises a Bavarian raupenhelm. Finally, the 6th seems a austro hungarian pickelhaube to me. Its difficult for me to comment on the total value of these helmets based on the single picture provided. However, assuming that the overall conditions of all the helmets is good, it is reasonable to expect that that the total value of all these helmets is a several (ten) thousand Euro's. I hope that my comment was helpful and I am sure that I probably made a few mistakes. For further information you should visit: http://www.kaisersbunker.com/" onclick="window.open(this.href);return false;
Best regards,
Edwin