Thought I'd post this here as general advice on savings for wood pellet based littler. Folks, I posted it on a deal, but it may help in general the rest of the time.
If you have an equine supply store anywhere nearby, it's the same gear they use for horse bedding (for horses, they throw bags of this on the floor, cut an x in it and water it - to convert into fluffy soft wood flooring for sleeping).
For example, if you're in Sydney, this mob in Kensington has 15kg bags for $17.95 (at time of last contact a few weeks back)
If it's good enough for the anal horse folk, then it should be fine for cats.
The next best I've found (and started with) in price terms (cheaper the more you buy and better than bricks and mortar pet stores) - Budget Pet Products
I'm not affiliated with either business, if that matters.
I got lucky in Bunnings one time they had 9kg bags for $2.50 on clearance. Bought them all.