Southwest Airlines via DealBase offers 1-way flights on over 200 routes with prices starting at $39.98. That's the lowest price we could find for select routes by at least $18. Book this travel deal by July 4 for travel from September 3 through December 18. Shop Now Tips On the DealBase landing page, click on "Southwest Airlines" in the top line to see this sale; we found lower fares within. We found a lower price on flights departing on September 10 from Long Beach, CA (LGB) to Las Vegas, NV (LAS). All prices, dates, and booking details were valid at the time of publication.