 What's the cheapest flight you can buy in the United States? I'll show you how you can use a simple trick to get up to $38 off the already cheap prices from budget airlines, ending up with a round-trip ticket for less than $40 total. To find these extra cheap fares, follow the standard advice of flying budget airlines during off-peak seasons, don't pay for luggage or carry-ons or seat assignments, be flexible with your dates, and buy tickets in advance. But there's one more trick you probably don't know, and that's to buy your ticket at the airport. I'm going to show you some examples and explain why that works. Let's look at a flight from Atlanta to Miami. Let's see, I'll pick some dates and search. $66.60 is pretty good, but I'm going to click on Monthview to find the cheapest dates. Ooh, look at these. That gives me a total price of $56.60. Not bad, but there's one more little trick. These airlines try to squeeze every little bit of profit out of the price, and you can use that to your advantage. Scroll down and look at these taxes and fees. You'll see the airline is paying airports and the government $29.16, keeping only $27.44 for themselves. They could just list this as the airfare, but instead they split it up and list it as a $20 carrier interface charge plus $7.44 airfare. They do this because they have to pay a 7.5% excise tax, but only on the airfare portion, the $7.44. By shifting $20 to this other fee, they save $1.50 on that tax for this ticket. So who cares? It's the same price for you either way, but this is where it gets interesting. In order for this little loophole to be legal, this carrier interface charge has to technically be an optional fee. What's the fee for? It's the fee for buying your ticket with an electronic carrier interface, which is just a fancy way of saying the internet. So the fee is for buying a ticket online, and this means you can avoid it by buying the same exact ticket in person at the airport ticket counter. Yes, they're called ticket counters because you can actually buy tickets there, though hardly anyone ever does. And just like online tickets, you can buy them months in advance and for other airports. Okay, so if you do all of that, this ticket will only be $36.60, round trip Atlanta to Miami and back. Here's another example of an allegiance flight from Las Vegas to Bellingham round trip for $29.82 and a Spirit Airlines round trip from Jacksonville to Chicago for $68.02. So what's the catch? It's this, only budget airlines use this tax loophole like Frontier, Allegiant and Spirit. And these cheap flights don't include a seat choice or food or boarding pass or even carry-on luggage for that price. But you can bring one personal item that fits under the seat in front of you. I use this bag, it's exactly the right dimensions and it's big enough for a short trip. So it's probably not worth it to make a special trip to the airport, but if you're there already or you're buying tickets for a handful of people, these savings can add up. But two quick tips. First, these ticket counters aren't open all day just for an hour or two before some flight is leaving from that airport. So plan ahead. Also, you'll need to know the full names and birthdays of all the passengers if you're buying tickets for more than just yourself. Okay, so what's the cheapest you can fly domestically in the U.S.? Two years ago, I got this round-trip ticket for $28.42 when some of us went to San Francisco for the day. Our BART train fare was almost as much as the airfare. And our ferry ride to Alcatraz was more. Another way to measure the cheapest would be cost per mile. The Atlanta to Miami flight I showed you turns out to be 3.16 cents per mile. But I found an even cheaper one by this measure, Santa Ana to Austin for 2.01 cents per mile. So for context, if you're watching this 100 years from now, that's about one gram of gold or about four hours minimum wage to fly a total of 4,000 kilometers. Let me know in the comments if any of you find a cheaper overall round-trip price or if you can beat my 2 cents per mile. Now I should say this isn't for everyone, but if you enjoy a good deal like I do, you might want to give it a try. And I know people like to complain about these budget airlines, but I think many of the complaints are from people not really paying close attention to the policies and fees, and then being upset when they get charged extra to print a boarding pass or change their seats or something. But if you do your research, carefully weigh and measure your bags and know exactly what you're getting into ahead of time, they're not bad for short flights. Finally, I have a cautionary tale for you. Late one night, I was waiting at a ticket counter buying a ticket. I overheard this poor woman standing next to me. You see, she was there on July 24th at 10.30 p.m. to check in for the 12.15 a.m. flight in two hours. Her ticket said July 24th and she was there on July 24th, but 12.15 a.m. was on July 25th. She had missed her flight by 22 hours and these budget tickets are non-refundable, so she had to buy a whole new ticket last minute. So just be extra careful with dates and times when you're buying a non-refundable ticket. The first time I ever signed up for Lyft was because I made a similar mistake with a hotel reservation in Denver once. I was there a day early and they were full. Okay, enough stories. Thanks for watching. I wish you success in finding cheap tickets.