Update 3/11: seems to have only been a weekly special, now showing $2.65
Stock will vary between stores. These were found in the fridges near the checkouts and likely will be restocked with other drink brands once sold out
Just walked in to Coles to see these in the fridges, looked online and it's $1 on special everywhere it seems.
Apparently got a new taste I'm tempted to try out because the last tasted like shit. For $1 it's worth a punt.
Yummy cold UHT milk with additives.
Edit: seems 2 are now gone from online, but should still be $1 in store