I have heard a few people saying how they got super cheap flights, like $1 (+ baggage) from Sydney to Gold Coast and things like that.
I don't have any time frames or anything but I would love to see cheap deals like that so if I see one I like, I can just quickly plan a short holiday.
I mean, $50 for a flight somewhere means its nothing crazy expensive and I could probably do a weekend somewhere to relax.
Flights at $1 would be very rare promos and them being advertised (and securing tickets) are quite different things.
Anyhow, a site like https://www.skyscanner.com.au/ or http://adioso.com/ allows you search from your Local Airport to "Everywhere" or "Domestic"