Low cost airplanes use a variety of sneaky tricks to ‘bump up’ the costs of their flights. Tempting £10 fares advertised online can quickly snowball and become £60 or £70 by the time you’ve got to the checkout.

Here’s how you can spot the hidden charges… and more importantly how you can avoid paying them!

1. Pay by debit card to save on the fees – Low frills airlines ramp up extortionate payment processing fees for anyone paying by credit card… and even debit cards! Currently RyanAir charge £6 per person and Easyjet a whopping £9… but not for much longer. The Office of Fair Trading has ruled that from December 2012 airlines will have to include the cost of the debit card fee in their headline price. However credit cards are exempt and will still be subject to additional charges at the airline’s discretion – so make sure you pay by debit card to avoid the extra fees.

2. Travel with hand luggage where possible and keep an eye on the weight for the return leg – by far the biggest charge low cost airlines will hit you with is checked in baggage. RyanAir charges £15 for your first bag (which really mounts up if you’re a family) and as much as £50 for sports equipment. It’s not just RyanAir, all the low cost airlines do it. The good news is that clever bag makers have built entire industries around making bags that fit the hand luggage requirements for no frills airlines perfectly. Here’s a cheap and cheerful one I found on Amazon (there are lots more to choose from. Searching on Amazon for “easyjet bag” or “ryan air bag” brings up a number listings).

Bear in mind that some airlines will weigh your hand luggage on the return leg because they know that you’re likely to have picked up a few tourist trinkets on holiday. Don’t get sprung on the return leg! If you want to pick up some bits while you’re away make sure you allow enough room (and weight).

4. Avoid eating food offered on the plane – Easyjet charge £4 for any sandwich in flight. And if you opt for any kind of hot food on the no frills airlines be prepared to take out a second mortgage (and be massively underwhelmed by the shrivelled lump of misery that you’re presented with). If you know you’re going to be hungry during the flight make sure you eat just before you get onto the plane. You’ll still pay a slight premium in the airport but nothing like as much as you will once you’re air bound. Also the food will taste considerably better as high altitude plays havoc with our tastebuds!

5. Don’t opt for pre-booked seats, get in the queue early – Low cost airlines took away traditional pre-booked seats which has led to a horrible arm flailing scramble when it’s time to board the plane. Predictably they offer the premium option of paying for a prebooked seat or ‘priority boarding’ but you’ll pay through the nose for it.  It’s currently £6 on Thomson and as much as £10 on RyanAir. Remember, whatever happens they have to let you on the flight. If you can stick it out sitting on your own for a couple of hours do! If not you can ensure you get a good seat or group of seats by camping out in the queue early so that you’re first in line when they call passengers onto the plane.

6. Untick any ‘added extras’ as you go through the payment process – Many low frills airlines will automatically tick a whole host of added services as you make your booking online. If you’re in a hurry and clicking through the pages quickly you may well get to the checkout and find that you’ve opted for 6 months in a hotel, 4 years car rental and all sorts of extras you desperately didn’t want.  Check each page carefully and uncheck the boxes so that all you’re paying for is the flight.

7. Organise your own travel insurance – One of the added extras a lot of low cost airlines encourage you to opt for as you go through the payment process is travel insurance. Of all the ‘added extras’ it sounds like the most appealing, however I’ve yet to come across one that isn’t vastly overpriced and light on benefits. Organise your own single trip travel insurance using a price comparison website or better still through one of the insurance companies on TopCashBack (we’ve just saved an extra £20 doing that on our annual insurance). If you know you’re going to be away a few times over the course of a year make sure you get annual cover for further savings.

8. Don’t be afraid to look elsewhere! It’s easy to assume that EasyJet, RyanAir and the other low cost airlines will always offer the best deal, but this isn’t always the case once you’ve factored in all the hidden extras, especially baggage. If you’re taking a family of 5 away for two weeks you’re not going to survive on hand luggage so your best bet may well be to plump for an airline that includes baggage allowance in the price.

I hope that helps!

I’d love to hear your comments if you’ve been stung by airplane charges or if you’ve come across sneaky hidden extras that I’ve not mentioned here.