British Airways, American Airlines, Finnair, Aer Lingus and various other airlines have round-trip flights from Austin (AUS) to Dublin or Inverness (DUB, INV) for $526-$571 with a connection. Flights November to March. Departures on Monday, Tuesday, Wednesday, and Sunday. 7-day minimum stay required. No Thanksgiving dates.
Inverness is cheaper, but has less availability.
A Carry-on bag and also a personal item is allowed for free on American. You can avoid paying for seat selection by accepting the randomly assigned seat at the gate.
Click for more details and booking links Cheap Flights: Austin to Dublin, Ireland or Inverness, Scotland $526-$571 r/t [November-March] (No Thanksgiving) – British Airways / American Airlines / Finnair / Aer Lingus