Jetstar has just launched a new route from Melbourne to Canberra.
Very cheap fares are available at the moment, from $55 one way.
Looks like plenty of availability out there throughout July - December.
^Sale ends 11.59pm AEST Wednesday 11 May 2022, unless sold out prior. Other conditions apply, see below. Travel dates: 1 Jul - 16 Sep, 4 Oct - 20 Dec 2022 and 10 Jan - 28 Feb 2023.