Southwest is celebrating their big 50th anniversary today with round-trip flights from Houston (HOU). Prices range between $98-$202 round-trip. Flights September 15th to November 3rd. Origin/Destination reversible. There are probably more destinations on sale than we list in this post. You’ll need to experiment on your own for cites we don’t have listed.
You may need to enter the “SAVE50” coupon-code during your search to see the fares, but so far, all fares seem to show up without the code.