Often Free Shipping (which really means the cost of shipping is included in the price) only refers to Domestic Shipping.
So if you are looking on eBaydotCOM, Free Shipping will refer to the USA, which is probably about 99% of the seller's business.
Always double check what shipping will be to Canda and to your postal code. This is in the Shipping and Handling tab.
If the seller is in the USA or the UK and using the Global Shipping Program, there may be Free Shipping to Canada, but there will still be import charges which cover applicable Canadian duty and sales taxes plus a $5 or so service fee to the GSP, for any item priced over $20CDN (about $18 USD). The Free Shipping only refers to the cost of shipping from the seller to the GSP plant, not to your doorstep.