Alaska Airlines and United have round-trip flights from Austin (AUS) to Honolulu (HNL) for $359-$384 with a connection. Flights August to October. Departures on Monday, Tuesday, Wednesday, Thursday, and Sunday. No Fridays or Saturdays. Extended weekends available. Origin/Destination reversible.
Priceline has “Express Deals” for about $341. With “Express Deals” the airline and exact flight are hidden until after purchase and those purchases are final. There is no 24-hour free cancellation for “Express Deals”. The flight is guaranteed to be on a major airline. Be sure to select the deal with 0 to 1 stops and a layover less than 3-hours.
A Carry-on bag and also a personal item is allowed for free on Alaska Airlines. You can avoid paying for seat selection by accepting the randomly assigned seat at the gate.