LitterLocker is a system I have been using with my cat for over a year to scoop and dispose of his litter more often, so it does not stink up the house. I was buying refills wherever I could find them; however, I found out the manufacturer of the product is Canadian and they offer refills through their own website with free shipping.
I use the LitterLocker II system. It allows me to scoop frequently without having to take out the litter. The container and bags lock in the scent of the used litter and allow you to add to the bag till it is full. It reminds me of the diaper disposal units I have seen. For an average cat, one refill will last two months. It is designed to work with clumping cat litter (so if you use another kind this might not work for you).
Before writing this post I purchased a six pack of refills for the LitterLockerII for $42.90. That works out to $7.15 per refill. I price compared with Well.ca (where I used to buy my refills when they had them in stock) and they sell the refills for $7.99 each. Since six refills is a year’s supply for one cat, I just saved myself just over $5. That may not seem like a lot, but in the lifetime of my cat, who should live another ten or so years, the savings add up.
If you have the original LitterLocker you can still get refills for it on this website. Also, if you do not have a LitterLocker but want to try one out, you can buy the system with one cartridge, six, or twelve. The box itself is pretty inexpensive and comes with a litter scoop (which I think is useless, so buy a better one).
No matter what you choose, enjoy free shipping across Canada.