Hi Jacko, and welcome to the forum.
Firstly, you'll need a basic wildlife licence from the state department, which is changing to online applications end of this month, here's the link
https://www.wildlife.vic.gov.au/keeping-and-trading-wildlife/online-wildlife-licensing-system-owls
Next decide if you are going to get a hatchling (young python under a year old) or an older snake, and you will need to buy/build an enclosure suitable for the size of the snake. If you get a baby snake, a click clack tub with a heat mat/thermostat is all you will need for the first year probably. Here's the link explaining how to set one up.
http://brendansreptiles.weebly.com/how-to-set-up-a-hatchling-python-tub.html
Most snakes eat mice or rats, (which you can buy already killed and frozen, so all you need to do is thaw it out to the required temperature to feed to your snake) the size of the mice/rat will depend on the size of the snake.
A good first snake is a Murray Darling Python (Inland carpet python) and they are quite cheap, they do grow to 6 or 7 feet though. Smaller pythons are Stimsons, another lovely snake.
I suggest having a good read about how to keep a python long before you even purchase one, here is a great link with easy chapters about snake keeping.
Definitely read the first 3 chapters, and they also have a chapter on different snakes/temperaments etc.
http://www.southernxreptiles.com/RA ARTICLE PAGE.htm
Hope that helps.
