You’ve heard about computer glitches that cause airlines to publish ultra-low bargain air fares.  Some cases include a Christmas gift from Etihad where travelers were able to grab up fares as low as $187 roundtrip -- including taxes, people -- from cities including Washington Dulles and San Francisco. Who can forget Delta Air Lines’ own Christmas gift of $7 -- yes, $7 -- roundtrip fares to Hawaii?

And until it decided not to honor them, United was selling first and business class fares to Europe for the bargain price of between $50 and $75.

How do these glitches happen? Mostly it’s human error, with someone dropping a zero or two. It can also be something buggy in the coding airlines use to upload their fares. If the fares are ridiculously low or too many people take advantage of a glitch, the airline can cancel the flight. But most times, airlines grit their teeth and take the hit.

Because we all have lives, we don’t have the time to sit in front of our laptops and constantly scan for these amazing deals. But thanks to the Internet and social media, there are myriad websites and groups that bargain hunters can follow to find these glitch fares.

The granddaddy of websites with deal alerts is Flyertalk. When a fare glitch happens, nine times out of 10 the are posted in the site’s Mileage Run Deals. If you don’t want to scan Flyertalk, then Glytch.com may be more your speed. for $5 a month, or $50 a year, the website will take your information and, using what it calls “sophisticated methods,” finds the glitches and emails them to you.

Other websites include The Flight Deal, The Points Guy, Extra Pack of Peanuts, Dan’s Deals and Flynous.

There are also forum websites that find and report fare glitches, including MilePoints, Fat Wallet, Canadian Free Flyers, Trip Adviser’s Air Travel and Slickdeals. If you want the deals to come directly to you, sign up for email alerts at airfarewatchdog or farecompare, whether you’re looking for fare glitches or the best bargains between city-pairs. Folks also recommend the UK-based website Holiday Pirates for fare glitches and cheap holiday travel packages, along with the Hot Deals forum at AnandTech.

Facebook is also a great place to catch air fare glitch deals, with groups and pages including: Cheapflights, Fare Deal Alerts and Secret Fares.

And if you should happen to snag a fare, then it suddenly canceled, you can file a complaint with the U.S. Department of Transportation's Aviation Consumer Protection Division (ACPD) here. you should also include a copy (not the original) of your airline ticket or itinerary sheet and any correspondence you have already exchanged with the company. But the agency advises that passengers give an airline the chance to resolve this issue before filing a formal complaint.

DOT rules require U.S. airlines to provide information on how to file a complaint with the carrier. This information must appear on their web sites, on all e-ticket confirmations, and upon request at any of the airline’s ticket counters or gates. A DOT rule requires that airlines acknowledge a written complaint within 30 days and send a substantive response within 60 days of receiving the complaint.

Although these places can't guarantee that you'll snag that bargain basement air fare based on an airline glitch, they do put you in a better position to take advantage of them when they happen. But be quick, because the fares tend to disappear as quickly as they are posted. And don't be disappointed if the airline chooses not to honor the fare.