I haven't seen this deal advertised anywhere so not sure if it is Australia wide and how long it is valid for. Last night I went to Sylvania (NSW) First Choice to buy a six pack. Guy at the counter told me about this deal. So I ended up buying a six pack of Mornington Brown Ale ($16.00) and picked up a free bottle of Supershine Extra Strong Ale (worth $15.00).
Definitely in Brisbane as in local catalogue. I assume extra bottle can be any beer which makes it a pretty good deal.
Well now I'm annoyed: I bought a six pack of Mornington Brown Ale from Ashfield, NSW on Wednesday.
This is the first I've heard of this deal :(
EDIT
Just looked at my receipt, there's an item listed as: %SPECIAL OFFER 0.00
I bet that's it.
Well I went in to enquire why I didn't get a free beer, and the guy at the counter beside the manager handed me a tin of Panhead XOA from beside his checkout.
Better than nothing, I suppose.
This stacks with the GOAT cashback deal.
https://www.ozbargain.com.au/node/442933
For ~ $2 (depending on location) you could get a six pack of GOAT lager and the Supershine mentioned in OP. $32 of beer for $2.
There's always a deal at my local of selected booze (mainly beer, some spirits and wine) for $10 (eg a 6pk or a bottle of wine) if you spend $10 in store.
Savings can sometimes be more than $10.