Avoid extra fees
Extra fees are the bread and butter of low cost airlines. Every year they catch countless unprepared passengers who end up paying much more than they had to.
For the most part, if you're prepared, follow the rules, and read the fine print you should be fine. Here's some common low cost airline fees.
1) Check-in fee
The majority of discount airlines require you to check in online and if you forget, they'll charge you a huge fee up to $150 to do it at the check-in desk.
2) Boarding card fee
If your airline requires you to have a boarding card ticket, you'll have to print it on your own printer (A4 paper only). Failing to do this will incur a fee.
3) Bag check
A carryon bag is almost always free but airlines are very strict about it's size and weight. They will carefully scrutinize your bag and if it doesn't meet their strict standards they'll require you to check it for an extra fee.
4) Change ticket fee
Double check everything before pressing the "purchase" button. If you filled in anything wrong on the form like the flight dates, your name or passport number, you'll have to pay an extra fee to change it. Sometimes the fee is so large that it's actually cheaper to just throw your ticket away and purchase a new one.