Very good price for a full gas cylinder. I just bought one along with the Sodastream connection. Couldn't find any under $100 around Brisbane.
They're located in Melbourne and it was $20 for delivery.
EDIT: They also have a 6kg bottle for $99 which is more economical but it's overkill to have that in your house.
Mod: Previous long running deal (duplicate exception, older than 6 months).