You are listing on eBay dot COM the US site which is serviced by USPS.
If you are determined to sell there, go to Offer Additional Service.> Choose Custom Location> Canada.
You can only use Flat Rate Shipping, so if your item is over 2 cm thick or more than 500 grams, you should check the canadapost.ca site for the actual cost of shipping to Vancouver, Toronto, and Halifax. They will differ and you will have to decide what your flat rate will be.
By the way, since you are using the dotCOM site, remember that Location refers to the location of the item, not your own.