( CNN ) -- Do n't simply saunter up to the boarding gate at a Spirit Airlines flight and think you can carry on your luggage for free . That 'll cost you $ 100 starting Tuesday . While discount carrier Spirit Airlines makes customers pay for most carry-on and checked luggage , its customers could pay up to $ 100 to bring their bags if they forget to pay in advance . The airline has raised other fees as well . Carry-on baggage is now $ 35 if purchased during online booking ( $ 25 for members of the airline 's fare club ) and $ 50 if purchased at the airport kiosk . Your first checked bag now costs $ 30 if paid during online booking ( $ 20 for fare club member ) , increases to $ 45 if purchased at the airport kiosk and increases to $ 100 if you check it at the gate . You can still carry a purse , briefcase or other small personal item for free . `` Our goal is for no customer ever to pay the $ 100 fee , '' said Spirit Chief Operating Officer Tony Lefebvre in a statement . `` By planning ahead and paying for bags before getting to the boarding gate , our customers are saving time at the airport and speeding up the boarding process . When our customers choose these time-saving , self-service options , our costs go down , and we can pass those savings along to our customers . '' Airlines making billions from fees . Spirit 's fees may seem extreme to some passengers , but most airlines seem to be making money from charging for services beyond the basic ride they provide . Additional revenue is generated by `` a la carte '' services such as snacks , preferred seating , luggage fees , commissions for hotel bookings and frequent flier mile sales to partners . Airline ancillary revenue is projected to reach $ 36.1 billion worldwide this year , according to the Amadeus Worldwide Estimate of Ancillary Revenue , an increase of 11.3 % over last year . That $ 36.1 billion is 5.4 % of global airline revenues of $ 667 billion . `` As far as fees are concerned , airlines ' attitude is , 'the more , the merrier , ' `` said Douglas Quinby , PhoCusWright 's senior director of research . `` Travelers who do n't have enough mileage status to enjoy any exemptions should plan for some extra spending when planning their travel , especially if they are traveling during peak times around Thanksgiving and Christmas , when overhead bin space will be hard to come by . '' Websites such as Kayak , Airfarewatchdog and FareCompare have convenient tables so travelers can plan in advance to some extent , Quinby added . Fees for 'extras ' likely to continue . Will passengers see more fees in 2013 ? There 's no end to the creativity of airlines to charge separate fees for things that used to be included in the price of a ticket , according to George Hobica , founder of Airfarewatchdog.com . Allegiant now gives a discount for paying with a debit card versus a credit card , and Virgin America has charged an extra $ 20 on some flights for seats closer to the front of the plane with early boarding , wrote Hobica in an e-mail . `` We might even see fees scaled by distance flown . If these fees are really about fuel consumption , why should a checked bag flown 300 miles cost the same as one flown 2,500 miles ? `` We may also see penalties -- er , fees -- for passengers who do n't print their boarding passes , pay baggage fees and check in online before arriving at the airport , '' Hobica wrote . `` Want to deal with a human at the airport ? You 'll pay for that . There 's no end to the imagination when it comes to new and 'improved ' fee structures . ''
Travelers can pay Spirit Airlines $ 100 fee by paying for bags when booking flight online . Airlines will make another $ 36 million this year through ancillary fees for bags , other services . Charge for credit card usage , extra leg room and window or aisle seats are likely to continue .