Where's the shopping cart? It's in the US.:-) You are on ebay.ca and Canada does not yet have the shopping cart feature. If you have items in a cart you can find them again by logging in at www.ebay.com .
Are you sure the seller ships to Canada? Does the seller know you are in Canada? Many American sellers offer 'free shipping' state-to-state because the postage cost is comparatively low. It costs more to lob things over the border so they usually charge for international orders. Have you clarified all this with the seller?
Usually if you have bought and want to pay for something but there is no shipping fee, if the items are in your Purchase History and you click 'Pay Now' you will not be able to until the seller adds a shipping fee (or specifies 'free shipping') on an invoice for you. I'd say contact the seller to ensure you are both on the same page, so-to-speak.