Southwest Airlines offers select 1-way fares to / from Dallas with prices starting at $52.10. (Click on "Southwest Airlines" in the top line to see this sale; all taxes are included.) That's the best base fare we've seen from Southwest Airlines this year. It's also a current low for select routes by $45. This price is valid on flights departing from Dallas, TX, (DAL) with arrival in Denver, CO, (DEN) on October 21. Book this travel deal by September 25 for travel from October 13, 2014 through March 04, 2015. Click here to see more routes.