Saw this this afternoon at IGA Stanmore by the train station. It's labelled as "Manager's special" so this may only be the Stanmore store's special.
Though Coles and Woolies are often cheaper than IGA, this is perhaps the cheapest I've ever seen this, as Woolies' cheapest I've seen is closer to $7.
Saw the same at Wantirna, VIC IGA this afternoon, so it might be at a couple of locations