If you're planning on traveling within Europe, Ryanair is a very affordable way to get to places. The check-in is smooth and accessable, and the flights are always on time. This is a wonderful airline for students on a budget. Tickets can be purchased online for an extremely low price. If your flight is going to take a couple of hours, I would suggest bringing a snack. You can buy drinks and snacks on the plane, but it's kind of expensive. This is where they make more money, and in-flight catalogues, because the ticket prices are so cheap. Other than that, it's a pretty good trip.
I wouldn't suggest it for someone who loves to fly in style and can't go lower than first class. All the seats are the same, but you do get to pick your seat. Another disadvantage in some cases is that the planes arrive at an airport in a town about an hour outside of Barcelona, so you will have to find transportation into the city. Luckily, there are coaches that go straight from the airport to the central bus station in Barcelona for a pretty affordable price.