Book soon! Frontier Airlines has a widespread sale with fares as low as $20 one-way or $39 roundtrip. Several routes can be found for under $100 roundtrip for fall travel. Check out where you can go! This sale ends tonight.
Travel on select dates from August through early October.
Most routes are only flown on specific days of the week so you'll have to click around to find available flights.
Tickets must be booked by 11:59 pm ET, August 21, 2019.
All fares are nonstop and work in the reverse direction as well.
There are many more routes on sale as well. The lowest fares may not be available throughout the entire travel period and you'll have to decline all extras to get the lowest price.
These fares only include one small personal item. Checked bag fees start at $30 each way when purchased during the initial booking. Larger carry-on bag fees start at $35 each way.
Seats will be assigned at random upon check-in for these prices. You may pay a fee to choose a specific seat.
Frontier offers the Works bundle, which can be added to any flight during the initial booking. It includes a standard carry-on bag plus a personal item, one free checked bag, seat selection (including stretch seating), priority boarding, flight flexibility, and refundability. This is a value if you want all of these amenities, but chances are you can get away with just adding what you need a la carte for cheaper.
Searching Frontier's site, I found flights departing San Jose SJC on Tuesday, September 10, returning from Las Vegas LAS on Friday, September 13, for $39 roundtrip.