Qantas (Pronounced KWANTAS) is the national carrier of Australia. Qantas Perth, Melbourne, Brisbane and so on. This is because Qantas has the strong brand name in Australia and has the trust of customers as well as the frequent flier program which serves more than 3 million Australians.
So, if you want to fly from Sydney Australia, getting a cheap flights from Sydney might be bit difficult. You will be better off to buy a ticket from another airline. Try Singapore airways, or Cathay Pacific. If you are flying to the Middle East, try Emirates Airlines or Gulf airways. These are the good airlines that will get you to the Asia destinations as well as Europe. Other foreign airlines such as Lufthanza or KLM fly from Australia but to be honest they have the worst in flight entertainment.
If you are flying to Sydney Australia, then getting a cheap flights to Sydney Australia on Qantas becomes more sensible and affordable.
You can compare the cheap flights to Sydney Australia by checking the websites of the Airlines shown on this page.