Paying 'Less' For A Plane Ticket? Check The Baggage Fee.

Travellers in a long check-in line caused by a computer malfunction at Spirit Airlines November 24, 2010 at La Guardia Airport in New York on what is considered the heaviest travel day of the year.  AFP PHOTO/Stan Honda (Photo credit should read STAN HONDA/AFP/Getty Images)
Travellers in a long check-in line caused by a computer malfunction at Spirit Airlines November 24, 2010 at La Guardia Airport in New York on what is considered the heaviest travel day of the year. AFP PHOTO/Stan Honda (Photo credit should read STAN HONDA/AFP/Getty Images)

If you think you've scored a "cheap" plane ticket, take another look to be sure.

Checked-bag fees can add major costs to your trip. But many travelers often fail to realize that cheaper, "low-cost" airlines are sometimes where you'll wind up paying high prices in checked-bag fees .

Spirit Airlines, known for its super-low fares, charges those outside its "fare club" $30 to $100 per checked bag depending on how the tickets are booked, per the Business Insider guide below. When the average price to check your first bag is $25, that's not such a stellar deal.

And be careful with some budget airlines abroad: On easyJet, you'll pay about $18 to $34 if you register your checked bag online. But make the mistake of waiting till the airport, and the price will be anywhere from about $50 (at the bag drop area) to about $70 (at the gate).

In short, budget airline fees can really get you down you if you don't plan ahead.

Of course, there are exceptions: Southwest is a winner in the baggage department, where both the first AND second checked bags fly free. And JetBlue -- which only recently started charging for checked bags -- costs $20 if you check in online or at a kiosk.

Want to know how much your next trip will really cost, all fees considered? Check out Business Insider's guide below.

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