I'm in Canada. The Kindle link works for me but the NYT trial is 14 days. I don't have a Kindle and it's unclear if I would be able to read it on my iPhone app or desktop.
Sony link works but I didn't attempt to get the free issues; in the past I think the store got me to the checkout before it refuses due to my Canadian-ness.
Kobo has 14 day free trials on all its newspapers and magazines, including NYT, WSJ and many Canadian choices:
http://kobobooks.com/newsstand
(I can only check Canada but I think it also works for US?)