Eugene to Las Vegas $24 one-way, nonstop, incl. taxes
This is one of Allegiant Air's crazy 1¢ fares, available for travel on December 23. Folks in Vegas can string together two 1¢ fares (though you must book them separately, as one-ways) to make a round-trip, departing December 21 and returning December 23, for $35 round-trip, incl. taxes.
Remember to uncheck all of those pre-selected frills that Allegiant is famous for, such as boarding and seat selection fees, and airport shuttles.