Generally in Aus you only pay if you break contract.
Once your contract is up you're free to go. I'm currently off contract, despite Telstra's best attempts to get me to join an other one with all sorts of 'special offer' deals. Funny thing is, now I'm off contract, my mobile bill is <$15 a month. It was 30-odd per month when I was on contract. 'Special Offers' indeed...
Two out of three people wonder where the other one is.