I have been buying HDMI, DVI, Firewire and various other cables from monoprice.com. Obviously, there is the issue of whether they ship to Canada or not, but their price for a 15' HDMI cable is $8.07.

I also have a membership at Sam's Club and their HDMI prices are not bad (compared to BestBuy-type stores). I think they want $20 for a 6' cable. Not bad when you're in a pinch.