SodaStream 60L Spare Gas Cylinder @
Harvey Norman and Domayne ($35 everywhere else)
Usually refilling is about this price, however Gerry is feeling generous by offering a filled spare cylinder at $19.
Get in quick before they pull the plug.
Credit to PriceHipster.
Still Available at Domayne Link for the same price
Edit 2: Looks like they have pulled the plug on Domayne too.