Frontier Airlines offers select 1-way fares nationwide with prices starting at $27.50. (Click on "Frontier Airlines" in the main paragraph to see this price.) That's the lowest price we could find for select routes by $50. This price is valid on flights departing from Charlotte, NC, (CLT) with arrival in Philadelphia, PA, (PHL) on March 13. Book this travel deal by March 5 for travel on select dates through May 20. Click here to see more routes.