Sighted at a couple Myer stores for $100, is the 25th Anniversary Optimus Prime. It should be at other store chains as well, for a little less, because it isn't a Myer exclusive.
Also note that the version being released here is the same as the Asian one, which doesn't have the DVD in it. It only has the comic and sound-gimmick thing. It also doesn't look as nice without the flap on the front, because it shows all the accessories, and doesn't have the extra artwork.