Jetstar: Fly between Brisbane and Sydney for $69
Jetstar have reduced their 'all day every day low fare' between Brisbane and Sydney to $69 on the Jetstar Light fare (10kg cabin, no checked baggage for each pax.) This could only be temporary, or may be implemented after successful sales of the fare. In some weeks, the fare is available for up to 6 days (Many Mondays, Thursdays and Fridays may be sold out or unavailable.)
There is also a fare which includes checked baggage - the Jetsaver, which is $10 more expensive.
$69 fares do NOT apply to the daily morning (8.15(ish)) BNE-SYD flight which leaves from the international terminal due to it ariving from Osaka. This flight is often late, but does allow the option to fly domestic StarClass for $279 (used to be $239 :()