For what one can only assume is a limited time offer, Overwatch Origins edition is on special for $69.95 AUD (down from $89.95 AUD). For $10.00 AUD (half the cost of the normal upgrade), you can upgrade your basic game to Origins Edition and unlock the in game skins as well as Winston pet in Warcraft, wings in Diablo 3, ingame portraits in Starcraft and card back for Hearthstone.

All you need to do is login to your battlenet account and click on shop. Purchase the Origins Edition and the game will charge you the difference.