Buying cream chargers not not illegal in Australia if they will be used for culinary purposes. Sale of cream chargers is also restricted to daytime in South Australia.
Cream chargers containing nitrous oxide (also known as laughing gas) can be used legally to whip cream, sauces and mouses.
Cream chargers can also be used to make flavour infused cocktails and alcoholic drinks. Flavour infusions is where the nitrous oxide when mixed with alcohol and food items will help dissolve the flavours from the food items into the alcohol quickly.