Flights can and usually are pretty expensive, but if you use websites that compare the flights from different airlines, you can easily save a little money. I would advise you to always search for the desired flight on more than just one website so that you can find the cheapest option available.
Kayak is the typical flight comparison website. You enter your destination, your preferred dates, and it shows you a variety of flights. You can then apply filters to focus on particular airlines or to limit the number of overlays.
Skyscanner works similar to Kayak. Here too you enter your preferred destination, your dates, and it will show you the possible flight routes. Skyscanner is known for being particularly cheap.
Opodo works just like Skyscanner or Kayak, however if you book a flight with Opodo, keep the price in mind. Often times, it will add an additional credit card charge that can sometimes even be half the price of your flight.
Momondo also compares flights from different airlines, just like Kayak. Momondo sometimes has special offers with which you don’t have to pay an additional baggage charge.
5. The Flight Deal
This website is primarily used in the United States and Canada, though it offers flights to destinations all over the world. It shows you cheap flights, but also features a variety of articles about specific destinations, offering insight and sightseeing tips.