The cost of paper

I've been transferring my amazon wish list from .com to .ca (yeah, I know, I don't have a job, but it's helping me organize my dissertation thoughts). It doesn't make much sense to me to stay with the the US version of the site, but I'm very puzzled by the price differences between the two.

Take for example this book:

on .com it retails for $13.57 US
but on .ca, it retails for $131.50 CDN

That's one hundred and seventeen dollars and ninety-three cents more! Almost ten times as much!

WHY?

It can't be that paper costs more here... we're the ones with all the trees!

(lucky for me, the university here has a copy that I can get my hands on...)