Catalogue item, buy 2 selected HP ink cartridges for $48. HP also have a cash back offer of up to $30 for every 2 cartridges purchased. https://www.ozbargain.com.au/node/287674
There are other cartridges available other than the one pictured, verified at two different stores. Also you can mix and match different model cartridges as long as they are all tagged 2 for $xx, where xx is the same amount.
Available online for delivery or pick up depending on local store availability.
Update: Woolworths is on the list of retailers for the cash back, contrary to the other ozbargain post regarding cash back.