Given the long history of the problem, it is sensible to double check shipping costs by clicking on the Shipping and Handling tab and checking that the actual shipping to CANADA.
And watch out for the Global Shipping Program.
If your item is over $20 CDN (about $18 USD) you may be required to pay duty and taxes. The GSP will charge these upfront, instead of on your doorstep. Unlike Canada Post and the CBSA, commericial shippers like PitneyBowes/GSP, UPS, FedEx and the like must charge these.