Cheap European Flights

1. Research.  As soon as you know your travel dates start researching the multiply discount European airlines for the cheapest flight.  The airline company you choose to fly depends on whether you are flying, for example, from Western to Eastern Europe, or just within Western Europe.  For example, Ryanair offers primarily flights to and from the UK while Wizzair offers primarily flights to and from Eastern Europe.  Cheap European flights are offered by discount airlines such as Easyjet, SkyEurope and Germanwings to name a few (check out Resources, below article, for a more complete list of cheap European airlines).

2. Timing. The key to getting cheap European flights is to reserve your ticket in advance.  The earlier you book the cheaper your ticket will be.  A lot of cheap European flights start the price at 0.01 cents (excluding tax, which can be around 30 euros).  If you wait even a month before your flight (depending on the season and destination) a 0.01 cent flight can go up to more than 100 euros (excluding tax).  
It pays to book cheap European flights as early as possible.

3. Season. Because travel has become cheaper within Europe more and more Europeans are traveling within Europe by taking advantage of the cheap European flights.  When planning a trip to Europe and within Europe make sure you research if you are going to be traveling during any long weekend holidays or festivals.  Chances are if there is a long weekend holiday or festival in your destination cheap flights are going to book up fast.  Europeans take advantage of the cheap flights and therefore book months in advance, buying off most of the cheaper flights.  If you do your research and book months ahead you are guaranteed cheaper European flights.

4. Payment.  Be prepared to reserve and pay for your cheap European flight online with a credit/debit card.  Make sure to read the fine print as many cheap European flights are non-refundable, but can be exchangeable for a fee.  Also keep in mind that most cheap European airlines have a strict luggage limit, so make sure you are not carrying more than you are allowed to unless you are willing to pay the fees.

Ryanair
Easyjet
Wizzair
SkyEurope
Airberlin
BrusselsAir
SmartWings
Germanwings
Air Polonia
Alitalia