For those living in Japan, Jetstar is celebrating their 2-year anniversary of Japan service by offering 7,000 yen fares between Narita and the Gold Coast (OOL) or Cairns (CNS) as well as Kansai -Gold Coast. With taxes, the return fare is still a reasonable 39,000 yen or so, depending on which of the extras you wish to purchase.
You need to book by Wednesday, March 18th at midnight JST, and travel must be between April 14th and July 14th. I couldn't find any info in English on their website (their Japan-based site is only in Japanese) but the following link provides the same info.
I was able to book a flight myself today and seats seem to be available for most flights, so this is not a typical bait and switch that I've seen elsewhere.