Low-fare, no-frills airlines can lure you with amazing prices (who doesn’t want to fly to a tropical beach for $39?) but are they a bargain? Add a few frills and the price rockets up.

We looked at four low-fare airlines – Jetstar, Tigerair, Scoot and AirAsia – to see where that final price comes from (and what you can do about it).

The heavy cost of baggage

Baggage is the most likely way you will blow your budget. Low-fare airlines usually include a “free” carry-on (7 kilograms for Jetstar and Tiger, 10 kilograms on Scoot or AirAsia for the basic ticket – a few kilos more if you’re flying business class).

However, pack your laptop and some boots and – especially with 7 kilograms – you’re almost at your limit. There are size restrictions, too. Oversize or weight limit (and they do often check), your bag will likely be put in the hold and you will pay the full rate, even if you are over by only a couple of kilos.

Hack: Pack light (doh!) and buy a digital luggage scale ($10-$20) to check the weight before you arrive at the airport. If you’re travelling with someone, share the load around.

It’s cheaper to pay for check-in luggage at booking time. Photo: Getty

Check-in baggage

You can pay to check in baggage but be sure to do this when booking. If you add baggage then, it’s one price, if you add it later the price goes up. Add it at the airport and the price goes up again. A lot.

For example, on AirAsia, to check in baggage for a Gold Coast to Kuala Lumpur flight, luggage up to 20 kilograms is $43 when booking; $50 after initial booking; $70 if you pay at the airport. On a Scoot short-haul flight, check-in baggage up to 20 kilograms is $24 when paid at booking; $40 at the airport.

On Jetstar, Sydney to Melbourne, a 15-kilogram bag paid for at check-in is $17 but $60 if paid at the airport. On Tigerair, Sydney to Melbourne, 15 kilograms is $17.50 when booking, but $75 at the airport. Remember, that’s each way. And excess baggage at a per kilogram rate of $15 or $20 adds up quickly. Pre-pay for 15 kilograms but rock up with 18 kilograms and you could pay $45-$60 extra.

Hack: Decide if you need the extra weight when booking. Calculate the cost of the airfare including luggage. It might be just as cheap to fly with a full-service airline that includes luggage. For example Virgin allows 7 kilograms carry-on and up to 23 kilograms checked-in when flying domestic, even with its cheap flights.

Take your seat

Seat selection is optional. If you’re two metres tall, it’s probably worth paying for extra legroom. But if you’ve average size and flying for an hour, is it worth it?

Tigerair charges from $4-$25, Jetstar from $5-$25, Scoot $7-27 and AirAsia (Melbourne to Kuala Lumpur) charges $20-$69 (more if you choose a seat after your initial booking).

Hack: Take your chances and log-in for online check-in as soon as it’s available. In most cases, you can choose a standard seat at no cost.

Do you really need to choose your own seat? Photo: Getty

Sky-high dining

A drink and snack-type meal (think carb-loaded pie, fizzy drink, some lollies) will set you back $15 or so a head on most flights.

Jetstar has a vegan-friendly menu and even a chicken parma ($12). Scoot gets good reports for its hot meals, but it’s hardly fine dining. A beer and crackers will cost about $10; or on Tigerair, an espresso martini is $15. A bottle of water averages $4-$5.

Hack: Short-haul at least, take your own food and water bottle to fill. Or eat before you get to the airport. If you insist on eating (and it does fill the time), pre-order – it’s cheaper.

Entertainment

Tigerair has recently released movies and TV programs – pay per view $6 for a movie, $2 for TV (BYO device).

Scoot TV (on the Dreamliner fleet) includes movies – at about $15 to watch on your own device. AirAsia charges $16 to watch on a preloaded tablet (not available on all flights). Jetstar charges $10 for movies, music, games on its screens.

Hack: Hit Netflix and load up your own amusement on your device before boarding. Take your charger and earphones and maybe even take a book.

BYO entertainment – for everyone you are travelling with. Photo: Getty

Booking fees

All airlines add a fee for credit, debit card and PayPal payments.

Hack: Pay direct debit to avoid the charge. Use credit card as a last resort (unless you’re obsessed by reward points). Consider a Jetstar credit card if you fly with the airline regularly (no extra fee). Be aware that some cards, such as American Express, can attract higher fees.

How it adds up

A (hypothetical) domestic flight ticket for $39 (one way), plus seat selection $15, plus a beer $8, plus pre-paid toasted sandwich and coffee $13, plus entertainment $10, plus … oops! forgot to pre-pay for baggage $60, plus “ticket and bag protection” $11.95, plus a 1.01 per cent credit card fee equals $153.48 (one way). Ouch!

As the saying goes, buyer beware.