IJN officer's cap price?

[Robert Shoaf]

I'm not a collector of Japanese militaria, but I would like to acquire a nice WWII era IJN offficer's service dress cap, the dark blue version.
I realize that they are not uncommon, but what is the price range for a nice example, not necessarily a pristine one, but in nice condition? I have seen prices all over the place on the internet.
Thanks.

Bob Shoaf