Yeah, that last bookseller is definitely taking the Mickey.
If you click on the individual links to the books, another page appears with a "check rates" link on it. I tried the first NZ seller - there's a Choose Country drop-down list on which the US appears (think $15 for fast, $13 for slow).
Just to be sure, I've sent them (Kauri Books) an email to see if they'll ship to the U.S. Will post here when I get a reply.
Abebooks is pretty good. I ordered a 627 Squadron history off a bookshop in the U.K. via Abebooks recently - the shipping rates they'd quoted weren't from Australia, so I got an automated message allowing me to accept / reject additional shipping charges of 4 quid.
I reckon it'll be fine, but I'll let you know what the Kauri guys say. Reckon you'll be able to get a copy for around $35 US all up, at your door.