Lately, Allegiant Airlines has been slashing fares on the weekend for travel two or three weeks ahead. Today is no exception. Allegiant mostly flies nonstop routes to and from Las Vegas and Florida (St. Pete and Orlando), with really low fares, such as Knoxville/Orlando $39 each way.
Check out our Las Vegas, St. Pete, and Orlando fare pages to see the sales. Usually, these routes go right back up on Monday morning, so buy this weekend.