As I understand, you have to have paid tax. IE: You earned over $6000 or whatever it is and you got $500 tax withheld throughout the year, and only got $400 back at tax time. Thus you paid tax and will get the rebate. If you got it all back, you get nothing. That's my understanding of it.

If you get things like youth allowance etc you get it anyway, so I'm getting it through that. There is a full list on the centrelink website