Can't answer about Australia. But here in the states, the old style cracker is almost impossible to find. You have to go online and order them (which is not hard to do).
Buying the old school "one at a time" screw together cracker is almost non-existant. Just go to a head shop and get the real whip cream dispensers. Expect to pay about $50 for a half pint one and more for the full size. If you can find one in a gormet/food shop, they can go for less than $20. It's all about demand.