I have noticed a change to some of the coupons coming my way that say "In the U.S. Only", and I will admit that I'm more than a bit intimidated to try couponing on the other side of the river. The prices are different, the stores are different and I wouldn't even know where to start.
Today I found a site that might help you out, it's full of coupons and codes for great savings that are for Canada and all of your stores! You can even find different coupon codes for your stores in your region - like deals and discounts for Chapters Indigo. I'll keep looking for more savings for you in the future, but this site is a great one to check for local savings!