American Airlines and United have round-trip flights from Dallas (DFW) to Nassau, Bahamas (NAS) for $336-$402, NONSTOP or with connections. Flights May, June, August, September, October, and November. Very few weekends available. Origin/Destination reversible. No Thanksgiving dates.
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.