San Francisco Bay Area to Denver

This Frontier nonstop usually runs about $297 round trip, and it just dropped to $87, a 71% discount and only a few dollars above the cheapest fare we've ever tracked on this route. Denver's mountain access, downtown food scene, and easy ski season ramp-up make it one of the most useful add-on trips going into winter. At this price it's worth grabbing a seat even for a quick long weekend.