Amazon.ca?
Oops - just sent this to Support. Will say the same thing here. We love your site immensely. I use it regularly for purchases/ideas for my daughter as well as my nieces (of which I have many) I would love to support your site by clicking the Amazon link and purchasing however - I'm from Canada. Purchasing from Amazon.com is often significantly more costly due to shipping and customs fees.
Perhaps you have tried it already but if not you should approach Amazon.ca for the same deal you have with the American site. I know several others in my area who use your site and wish to support in this way as well, but cannot justify the extra cost.