LG Optimus One (Android 2.2 Froyo) UNLOCKED @Crazy Johns Prepaid Pack for $279
This was posted 2 years 5 months 21 days ago, and might be an out-dated deal
LG Optimus one comes with Android Froyo 2.2 and pretty good specs see here http://www.crazyjohns.com.au/lg-optimus-one-p500/
cheapest I could find on the net other than this is $309 from optussolutions.com.au which comes with GPS kit as bonus but contains lot of optus junk which people have reported they cant get rid of and annoying the hell out of them see here http://forums.whirlpool.net.au/archive/1533982 others are around #349 unlocked.
Comparing it with a prepaid pack from Crazy johns unlocked I think is a good saving for anyone interested.