I’m not sure but I think most Canadians get this as part of the deal but us Brits have to buy them at $10 when we arrive, they have been available to buy by post previously and they can now be purchased online BUT they cost $10 at the airport, about £6.30 if you go online they want £10.00 and £3.00 postage, thats £13.00 more than double the cost!! OK it saves you waiting in line at the airport to buy one but I would rather keep my money and wait a little longer in one part of the airport.
Just my feelings you may want to buy ahead of time and then wait for your luggage a little longer, your choice. ;D
Cheers Amandalou :-*