If you are not using Paypal (Australia) yet, you can easy get benefits of these offers by creating new account with Paypal. It is free and easy to set up and you can save up to 200$ by booking your next flight or accommodation with offers from these companies. Just read fine print as they have different rules.
FlightCentre: Receive 10% cash back when you spend over $200 on any flight. You will receive 10% cash back to your PayPal account, up to a maximum cash back of $100.
Webjet are rewarding customers who book and pay for their international flights using their PayPal account with $150 cash back. Your booking must have a minimum value of $1,000 and excludes flights to and from New Zealand and Jetstar flights
Besides flight bookings you can save on hotels bookings with Agoda. It offers $50 cash back into your PayPal account when your booking value is $200 or greater. Limited to the first 800 eligible bookings.
Offer ends on 31st of October or cash back budget is used up, whichever occurs first.
Of course you need to check other alternatives, as I couldn’t find good prices to destinations I want to fly with these companies, but may be you’ll have more luck and will be left with more spending money on you next holidays.