Sounds like a plan mate! My brother left the UK last november with only his open-ended return ticket to Perth and about £500 in his pocket!
So far, he hasn't left Perth, is in the same hostel as the day he arrived and doesn't know exactly when he is going to go off travelling.... but he gets casual work easy enough (earning reasonable money) and is having the time of his life!!!
He is currently riding those pedal taxi bikes around Perth and earning about $20 per hour plus tips.... when that finishes, I think he is going to work on the farms in Northern W.A for the winter, once that's finished he'll hopefully have enough money to see more of Australia!
Good luck to you mate!