American Airlines has round-trip flights from Dallas (DFW) to Cancun (CUN) for $235, NONSTOP. Flights in May. Departures on Monday, Tuesday, Wednesday, and Sunday.
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.
Read More Nonstop Flights: Dallas to Cancun $235 r/t [May] (Mon, Tue, Wed, Sun) – American Airlines