OzGameshop have Halo 4 on pre-order for $49.99.
There seem to be two different ones on the website, one for $64.99 and this one for $49.99.
Get in while it's available!
As per the website:
This is a pre-order - the item will be dispatched to you on or before the release date of 06/11/2012 - subject to change by the publisher.
Please note: this is the NTSC-J version of the game which is fully compatible with PAL systems.