I got mine from Cranberry Lane in Port Coquitlam. They have a store you can go to and they will ship it by Purolator. It's been a long time since I ordered it because I got a HUGE bag the last time. We just picked up some clean water jugs and used a funnel to pour it in. I'm set for quite a long time.
There prices are not bad at $8.75 for 1 kg. or $29.95 for 5 kg. The kicker is the dangerous goods fee that Purolator charges over and above the shipping fee. It's $35.00 which is why I got a large bag. Mine was 25 kg. and I'm not sure if they still sell one that big.