Ending today, Southwest Airlines offers 1-way fares nationwide with prices starting at $64.60. (Click on "Southwest Airlines" in the top line to see this sale.) That's the lowest price we could find for select routes by $39. This price is valid on flights departing from Ontario, CA, (ONT) with arrival in Las Vegas, NV, (LAS) on December 14. Book this travel deal today for travel from December 6, 2014 through February 11, 2015. Click here to see more routes.