There are several options for flights to Sydney, Australia. Some popular airlines that offer cheap flights to Sydney include Qantas, Virgin Australia, Air New Zealand, and Singapore Airlines. You can book flights directly through the airline's website or through a travel agent. The cost of the flight will vary depending on the time of year and the airline you choose. It is recommended to book flights in advance to get the best deals.

There are several ways to find cheap flights to Sydney:

1. Book in advance: Booking your flight well in advance can save you a lot of money. Airlines often offer special deals and discounts for early bookers.
2. Compare prices: Use online comparison sites such as Skyscanner, Kayak, or firstflytravel to compare prices from different airlines and travel agencies.
3. Be flexible with your travel dates: If you are flexible with your travel dates, you can often find cheaper flights. Try searching for flights on different days or at different times of the day to see if you can find a better deal.
4. Look for deals and promotions: Keep an eye out for deals and promotions offered by airlines and travel agencies. They often offer special discounts and promotions to attract customers.
5. Consider budget airlines: Budget airlines such as Jetstar and Tigerair offer cheaper flights to Sydney, but they may have additional charges for baggage and other services.
6. Use rewards points: If you have rewards points or frequent flyer miles, you can use them to book flight tickets.
7. Check alternative airports: Sometimes, flying to an alternative airport close to Sydney (e.g. Newcastle, Illawarra Regional Airport) can be cheaper than flying directly to Sydney.