If the seller is not enlisted in the "Global Shipping Program" you will pay duties and taxes to the delivery person at the time of delivery or when you collect the item from the Post Office or UPS store etc etc....
Only items valued at more than $20 Canadian are subject to import duties and if the vast majority of items shipped via the Post Office get through without charges even if they were eligible for charges.
If the seller is enlisted in the "Global Shipping Program" you will pay duties and taxes at the time you pay for your purchase.
If the seller uses the Global Shipping Program that information is displayed near the top of the listing as shown in the screen capture below.
