>>1423562https://www.bikezonefitzroy.com.au/a/touring-bikes/fuji/vic/fitzroy/fuji-touring-2019/103352964https://www.bikezonefitzroy.com.au/a/gravel-bikes/fuji/vic/fitzroy/fuji-jari-2-3-2019-dark-green/104510353not op but it's gonna be $1000- $2000 straya dollars for a -good- new touring bike like above for example, and then a few hundred more for racks and decent waterproof panniers.
If you were competent, and had time on your hands, you could do it for significantly less, like under $500 easy, with a used bike, like a nice rigid 90s mtb or a used tourer if you could find it, but you would want to rebuild and modify it -well- before you went, so it's in perfect mechanical condition.
You can also get away with touring on just about any bicycle too but especially if you wanted to go anywhere on the interior you're gonna run into mountains and then not having super low touring gearing and a very stiff frame intended for swaying loads, is going to hurt. There are cool reasonably flat coastal routes though and island hopping for which a less competent bike would hold up better.
>>1423405sounds awesome. post more photos and stories.