Seagate Backup Plus Desktop 3.5" 8TB G2
Lowest on staticice is $478 + delivery.
http://www.staticice.com.au/cgi-bin/search.cgi?q=seagate+bac…
Don't forget cashrewards
http://www.cashrewards.com.au/ebay-australia
Original CDICKSMITH30 deal
https://www.ozbargain.com.au/node/213196
*Item was located via phone's browser, but could not find this via my desktop, so it's possible that you can find a lot more items using mobile versions of the site.
Looks a good deal, but personally I'm not sure if I want to store so much info on one HHD since I heard reliability of Seagate is not on a par with WD or HGST…