Note some flights sell out in 2 days' time, and others are while seats last, so you'll want to get in quick.
Qantas Domestic Australia wide flight sale.
Examples (prices are one way):
Melbourne to Hamilton Island from $139
Sydney/Melbourne to Perth (and vice verca) from $199
Adelaide/Sydney to Sydney/Adelaide from $129
and many, many more - this is all of Australia on sale!
Alliance: OneWorld
Airline: Qantas
Virgin has/or will probably match and has double SC starting Monday so might be worth a wait