See previous posts for comments:
https://www.ozbargain.com.au/node/764852
https://www.ozbargain.com.au/node/753722
https://www.ozbargain.com.au/node/750144
AusPost also claim to Get $75 off your first year's premium when you buy Comprehensive Car Insurance online.
Mod 11am: Cashback rate is now 13% (from 14%).
Oh the unlimited money hack!