Book quickly! Frontier has a great promo code sale that ends tonight! Take up to 90% off the base fare for travel this fall and 50% off the base fare for winter travel. Fares start at just $33 roundtrip.

Use promo code SAVE90 when booking on FlyFrontier.com to take 90% off the base fare for nonstop domestic flights on Tuesdays and Wednesdays, through December 18, 2018, with a 7-day advanced purchase required. Blackout dates apply: November 17-27. For winter travel, use promo code SAVE50 to take 50% off the base fare travel on Tuesdays and Wednesdays, from January 8 - March 6, 2019. There is one lone blackout date on February 19.

The discount does not apply to taxes nor Frontier's online booking fee, which is labeled a "Carrier Interface Charge". This means some routes still won't have a very big price drop even with the big sticker shock of 50-90% off. However, there are plenty of routes where we are seeing deep discounts. The discount can also be applied to one-way flights.

If you are unfamiliar with Frontier Airlines, please read our guide on Everything You Need to Know Before You Fly Frontier.

There are specific route exclusions for both the 90% off and the 50% off promo code sales. You may have to click around to find available dates since Frontier operates about half of the route network on just a few days each week. Click on the fare details for more info on exact dates each route is available.

Tickets must be booked by 11:59 pm ET, October 1, 2018.

A sample of nonstop fares that work with the 90% off promo (may also work for the 50% off promo with higher fares)

Greenville to Orlando $33 roundtrip

Charlotte to Orlando $36 roundtrip

Atlanta to Orlando $37 roundtrip

Atlanta to Cincinnati $49 roundtrip

Detroit to Orlando $54 roundtrip

Austin to Charlotte $68 roundtrip

Denver to Salt Lake City $68 roundtrip

Grand Rapids to Tampa $69 roundtrip

Atlanta to Salt Lake City $69 roundtrip

Minneapolis to Raleigh $69 roundtrip

St. Louis to Las Vegas $70 roundtrip

New York to Orlando $70 roundtrip

Philadelphia to Orlando $70 roundtrip

Raleigh to Houston $70 roundtrip

Austin to Santa Ana $70 roundtrip

Raleigh to Phoenix $71 roundtrip

Denver to San Francisco $71 roundtrip

Portland, ME to Orlando $72 roundtrip

Seattle to Austin $72 roundtrip

Milwaukee to San Diego $73 roundtrip

Atlanta to Denver $74 roundtrip

Nashville to Las Vegas $74 roundtrip

Cleveland to Phoenix $75 roundtrip

Denver to Santa Ana $75 roundtrip

Tampa to Las Vegas $77 roundtrip

Philadelphia to Denver $77 roundtrip

Atlanta to Las Vegas $77 roundtrip

Denver to Washington D.C. $78 roundtrip

Los Angeles to Atlanta $79 roundtrip

Atlanta to San Juan $101 roundtrip

A sample of nonstop fares that work only with the 50% off promo

Sacramento to Las Vegas $54 roundtrip

Charlotte to Philadelphia $70 roundtrip

New York to Miami $82 roundtrip

Memphis to Las Vegas $82 roundtrip

Albany to Orlando $87 roundtrip

Chicago to Orlando $91 roundtrip

Cincinnati to Las Vegas $92 roundtrip

Cleveland to Las Vegas $102 roundtrip

Many more routes are available and these fares all work in reverse as well. Lowest fares may not be available throughout the entire travel period. You'll have to decline all extras to get the lowest price.

Keep in mind that Frontier charges extra for any bags larger than a small personal item (small backpack, large purse, etc.). Pack super light to get the lowest price. Checked bag fees start at $25-$30 each way. Larger carry-on bag fees start at $30-$35 each way.

If you want to avoid all extra fees, read How to Pack in Just a Personal Item Sized Bag.

Above image by Colin A. Pierce via Shutterstock.