Qantas has round-trip flights from Dallas (DFW/DAL) to Sydney (SYD) for $815 NONSTOP, or Melbourne/Brisbane (MEL/BNE) for $807 with a connection. Flights February to September. Australian ETA (a Visa) required.
Note: Priceline seems to have this priced lower than Google/ITA and most other websites at the moment.
Note: Some small OTAs on SkyScanner may have this for $753. If you plan on booking there, beware of any site that charges a fee to cancel a ticket within the 24-hour “free” period. Use unknown booking sites at your own risk.
Read More Cheap Flights: Dallas to Sydney / Melbourne / Brisbane $807-$815 r/t – Qantas