4 reasons the cheapest airline sales may not be good deals

Even in a pandemic, the idea of a free flight is enticing. That’s because whether you’re paying cash or using points and miles, everyone loves to save money.

That’s why my heart skipped a beat when I saw a promotion from recent Frontier Airlines advertising, in the airline’s words, a “100% off” flash sale. I was immediately intrigued by the sale and spotted several options I’d be interested in booking for early 2021 dates.

I was prepared to book at 100% off, hoping I'd just be on the hook for about $5.60 in taxes each way as is common with award tickets, but then noticed that the ticket wasn’t free at all. In fact, it was around the same price as other full-service airlines. Sales like this aren’t uncommon, but should you book?

Here are four reasons why that “completely free” flash sale ticket might not be the best deal.

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“Free” sales are usually off the base fare

I took note of some of the terms and conditions: must book by Aug. 19, can only travel Monday through Thursday and Saturday, must book a round-trip ticket. That all seemed reasonable.

I checked the dates of my preferred itinerary, a round-trip, nonstop flight from Newark (EWR) to San Juan. Everything seemed normal, aside from Frontier’s website loading slower than usual, ostensibly from high traffic.

When I went to checkout, I noticed the fare was about the same. I tried again, thinking I’d forgotten to enter the promo code. I quickly realized the “100% off” sale applied to the base fare and didn’t include charges like taxes and fees. Sure, the promo shaved nearly $80 off the base fare but after adding taxes and fees, I didn’t save much money at all. Note that while taxes are a pretty set portion of the fare, "carrier-imposed fees" can be more easily manipulated.

In fact, the fare was on par with a United Airlines flight from Newark to San Juan in basic economy. United’s basic economy fares are more restrictive and punitive than any of the other U.S. carriers, though is still essentially on par with the rules of flying an ultra low-cost carrier. However, with United, the basic economy experience can be made better with elite status or an eligible cobranded United Airlines credit card when the card is used to book the flight.

In this case, if you are going to book a cheap flight -- and you aren’t saving more money on an ultra low-cost carrier -- you’re often better off booking on a full-size carrier.

Related: Is it cheaper to book a Spirit Airlines flight at the airport?

Don’t forget to choose your seats

Frontier serves dozens of cities in the U.S., Mexico and the Caribbean. True to its no-frills pedigree, the airline charges fees for most extras, including checked and carry-on bags, advance seat assignments and airport check-in.

After picking the flight with this sale, I was taken to a page to choose a bundle of perks. For an extra $60, I could choose to bring a personal item, carry on and checked bag, seat selection and priority boarding. For a whopping $160 extra, I’d get all of that plus flight flexibility and the ability to get a refund.

I decided to skip the bundle section to check out the seat prices. The cheapest assigned seats started at $17 each way for seats in the back of the plane, all the way up to $60 for seats with more legroom at the front of the plane. Carry-on and checked bags (beyond the one free personal item such as a purse or small backpack) were similarly pricey, at $39 and $34 a pop each way.

That “free” flight was starting to really add up.

Related: How to pack in just a Spirit Airlines free personal item

Discount programs can yield more savings 

In addition to its loyalty program, Frontier offers more ways to save on travel through its Discount Den Fare Club. At $59.99 per year, members have exclusive access to Den deals and Frontier’s lowest fares.

The savings are even greater for families or if you tend to travel in groups. So long as the member is on the reservation, any discounted fare can apply to up to six travelers on your reservation.

Frontier claims that members save an average of $114 per year, which is almost double the cost of a Discount Den membership. The premise is that members will enjoy savings on flights that outweigh the cost of the annual fee.

You can score some pretty cheap flights through Discount Den, but unfortunately, that discount didn’t apply for Frontier’s most recent sale. TPG’s Richard Kerr, who has a Discount Den membership noticed that the regular fares cost the same as discount den fares. The money he paid for Discount Den didn’t save him anything in this case. But on the flip side, sometimes you'll need that Frontier Discount Den or Spirit $9 Club membership purchase to get the lowest fares, so factor that cost into the overall equation.

Related: Everything you need to. know before flying Frontier Airlines

Fixed $$ promos are better

All those things being true, these sales can work in your favor -- sometimes.

Frontier periodically offers promotions that truly do shave a significant amount of money off the base fare. In the last year, we’ve seen some pretty solid deals through Frontier and Discount Den, like the recent $11 flights nationwide. These were actually BOGO $11 flights for those with the previously mentioned Discount Den membership.

Last fall, I found a flight from Newark to Las Vegas (LAS) for $30 total.

That price included the base fare and taxes and fees. Sure, you still have to add on the cost of bags and seat selection, if you want those things, which will bring the total cost up. But even after I’d selected seats (I decided to not bring a full-sized carry-on) my total costs hovered around $40.

That’s certainly less than Frontier’s most recent promotion, or if I’d decided to fly a legacy carrier to Las Vegas, as transcontinental flights can easily run you $200 a flight -- even in basic economy.

Related: How to get started with points and miles

Bottom line

It’s important to read the fine print -- and taper your expectations -- when you book deals advertised as some crazy percent off. There’s a reason why budget airlines like Frontier and Spirit, have remained profitable (during normal times), and that’s by charging for services like seat selection, ticket printing and onboard snacks or sodas.

If you are trying to score a “free” flight or one at a significant discount, you’re often better off using points and miles or scoring a deal through a promo that shaves off a significant amount of cash by offering flights at a fixed amount of cash. Either way, just know that nothing’s ever really free -- there are almost always strings attached.