I believe this is the cheapest price in Aus at time of posting. Also, they have a special running where you purchase any TV that's 50" or larger, and get 10% back as a gift card. Have a great day :)
Don't forget you also get a free movie rental & 3 months of music with the Chromecast purchase.
Mentioned a few posts down https://www.ozbargain.com.au/node/195358