I've ordered off ebay for my pins. Last year I just cruised the listings for a while, looking for reputable sellers and the best deals. The one I bought from was out of Florida (sorry, can't remember her name) had listings for "grab bags" of Disney pins, all official, all tradeable in the parks. I actually bid and won 3 auctions of hers at the same time to maximize my buying power (she offered a better deal on shipping if you won multiple auctions). The pins didn't take that long to get here and if I remember correctly, I only had to pay taxes and the Canada Post fee for processing ($5), no duty. In the end I think I wound up paying around $2.50 per pin. I didn't know what would be in the "grab bags" but I did end up keeping about 10 out of the 50 I ordered because they were good ones, and we took the rest with us and traded them in the parks. It was great! We had a blast, especially Connor. We'll do that again for the trip in January.
Spend some time looking at the listings, look for sellers who have really good feedback, that are willing to ship to Canada, and that ship by mail, that way you'll save as much as possible on taxes/duty/fees.