I normally buy the 6mm Fire Wood Pellets in 15kgs packs from my local fuel depot for £4.29 (28.6p/kg), but that is a long car journey just for cat litter. At £4 for a 30L pack (I weighed a few and the average is 18.4kgs) that is just 22.2p/kg, and it is for 'proper' cat litter (the cat litter, if you get the decent stuff, is light in colour which makes it easy spot and remove the poops). The fuel version I normally buy is all manner of colours and doesn't always break down to dust so easily. I emptied my local store's shelves, but Customer Services say it is a nationwide deal. Beware, 18.4 kgs is heavy, especially when you have 7 sacks in your trolley!!