You can watch F1 for free in Australia, but your opportunities are limited. For one, you can watch F1 practice and qualifying at no cost on Kayo Freebies. However you won't be able to watch the main race live via Kayo Freebies, you'll have to pay for a full subscription. The Australian Grand Prix will be the only F1 race widely accessible for nothing, being live and free on Channel 10 and 10 play.