While most sellers include the shipping price for their listings, allowing eBay to invoice for them, some do not.
It is also possible that there is no shipping price because the seller does not ship to Canada. Go back to the listing and check on the Shipping and Handling tab.
And, if there is a shipping price to Canada, you should be able to click on a Pay Now button,which will give you an invoice and direct you to your Paypal account.