Spirit Airlines offers roundtrip flights to Las Vegas from select cities in the U.S. with prices starting at $66.20, as provided by ShermansTravel. (Click on "Spirit.com" in the main paragraph to see this sale; all taxes are included.) That's the lowest price we could find for select routes by $18. This price is valid on flights departing from San Diego, CA, (SAN) with arrival in Las Vegas, NV, (LAS) on September 16 with return on September 24. Book this travel deal by September 3 for travel September 1 through October 31. Click here to see more routes.