Frontier has round-trip flights from Dallas (DFW) to San Diego (SAN) for $118, NONSTOP. Flights September to November. Departures on Monday, Tuesday, Wednesday, Thursday, and Saturday. Extended weekends available. Origin/Destination reversible.
Frontier fares do not include a free carry-on bag. Only a small personal item, like a Jansport SuperBreak backpack is free. You can avoid paying for seat selection if you accept the randomly assigned seat prior to boarding.
Frontier seats only have 28-inches of pitch; 2-to-3 inches less space than most other airlines.