This deal will probably end later today.
Southwest has round-trip flights from Houston (HOU) to Honolulu, Maui, or Kona, Hawaii (HNL, OGG, KOA) for $318-$387, with a connection. $155-$192 each-way. Flights August to October. Origin/Destination reversible.
Use the “BEACHBOUND” coupon-code.
Cheapest flights are to Maui or Kona for $318. Honolulu is more expensive about $380.