JetBlue and Delta have round-trip flights from Austin (AUS) to Nassau, Bahamas (NAS) for $375-$378 with a connection. Flights December, January, May, and July. Weekends available. Origin/Destination reversible. No Christmas dates available.
A Carry-on bag and also a personal item is allowed for free on Delta. You can avoid paying for seat selection by accepting the randomly assigned seat at the gate.