Note: please read the comments or notes below, you may be able to pick one up for as little as $10 C&C
Starlink: Battle for Atlas Starter Pack (Includes Game, Controller Stand, and Merchandise) $9.95 + Delivery from The Gamesmen.
Not as cheap as the $5 deals that have been around, but this is the cheapest one I can find atm.
If you missed out on those deal you may want to look into this (but take delivery into account which is around $9 unless you can pick it up in store).
Especially since the game is old now, and the physical copy with merchandise will probably become less available as stores run out of stock (I can't imagine shops buying more stock to sell at $5 because there wouldn't be any profit in it).
PS4 https://www.gamesmen.com.au/starlink-battle-for-atlas
XB1 https://www.gamesmen.com.au/starlink-battle-for-atlas-1
Note they are $10 C&C at some Big W stores (credit to Buy2Much)
https://www.bigw.com.au/product/starlink-battle-for-atlas-st…
Note: take a look at the ones sold from the Gamesmen on eBay for $17.81 delivered, in one of the comments below (credit to juiciness).
For those eBay fiends.
$17.81 delivered on their eBay store with PBOLT15. eBay Plus Required.
PS4
https://www.ebay.com.au/itm/Starlink-Battle-for-Atlas-Starte…
Xbox
https://www.ebay.com.au/itm/Starlink-Battle-for-Atlas-Starte…