Motorola F3 on Optus Prepaid for $39
The phone is locked though.
If your looking for maybe a phone for your kids or something? this is probably one of the most durable phones to date (there's same interesting clips on youtube with people basically trying to destroy the phone with no success).
This phone does what it's mean to do, be a phone. Battery, voice calls are apparently excellent. Screen uses e-ink which has very little power consumption. But yeah, if your looking for a phone with more than just voice, you probably won't be happy with this.
Currently considering replacing my Samsung P300 for this.
Someone mentioned 12.5 days standby. o.O