Just picked up God of War: Ascension @ The Good Guys Cranbourne. Not many games there. Everything on bottom shelf is 50% off clearance. The old guy told me everything is $19 on that shelf. There were about 8 copies of God of War: Ascension. Rest of the games were not that good. COD MW3 $19 and a couple of PS move games.
It did scan at $39 but the guy wrote up a cash sale invoice for it. So my bet it may not be nationwide.
My guess is that it was probably a mistake but get it while you can @ Cranbourne ;)
$19 definitely the cheapest you will find :)
Must be one of the games they didn't have stock of 2 weeks ago =/