You're in NZ. Have you ever had to pay $30 for shipping a $2.39 book from the US?
Given that English is the official language of New Zealand, they don't have as much need to order books from the US as the rest of us. Not that I order them from the US anyway, I order them from Britain. Thankfully, Amazon UK has free shipping of books to Denmark.
That depends on availability, really. I have a commercial intermediary in the US, and just this week I had to ship a lot of rare books from Australia to the US (the sellers wouldn't ship to Russia), and holy crap I'm broke again. Plus I have Australian acquaintances (but not close enough to drag them into this whole shipping business) who reported problems with availability of some current stuff. So, I think, if impersonal-you have any special interest at all (and we're on GOG, of course we do) where physical stuff matters, you can't help but be boned by shipping at least occasionally.
Edit: for a direct comparison, I also bought four books for the swindle. Buying them in the UK would've cost me £40+, the swindle versions were $10.79 total.