It’s $400 in the store with free shipping (I think worldwide, but I’m unsure) , and there’s ample supply, so that Amazon price is trying to hit uninformed customers (and at this price I don’t think anybody would be uninformed).
I got it on the second KS for $250 including shipping. So, given that it includes a magnificent, useful insert, it was cheaper than what I had to spend on Gloomhaven so it is playable within my time constraints.
I do agree $400 is waaaay too much, though. There will be a 2.0 version of the game by 2020 or 2021, so I would recommend people interested to wait for that KS. I waited one year and a half since I became originally curious on the game till I was able to buy it on KS (and it was quite steep even then).