I've seen Aldi's Di-San selling for $10 per 3kg. Otherwise it sells for around $3.50 for a 1kg container.
Unfortunately Aldi isn't everywhere and in some places like W.A. it's no where to be found. I like to buy supplies as needed to avoid carrying a 12 month supply.
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Steve, Di & Ziggy We named our Motorhome "Roadworx" because on the road works "On The Road Again" Ford Transit with 302 Windsor V8 conversion, C4 Auto, 9 Inch Ford Diff All Lighting L.E.D., 260 Amp/h AGM, 530 Watt Solar + Kipor Backup Gen.