Free fish tank heaters?

I am really short on money and can't really afford a heater right now, I'm only young so I haven't got a job yet... and my parents aren't rich either... SO i was just wondering if anyone had any old heaters that I could have, or even buy for cheap?? I only need one... and it must be for an out door pond... PLZ help! My fishies aren't comfy in this pond at the moment... LoL... Thanx it would really help... Oh, and I live in Australia...