This graphic explains when to buy your airline tickets. It has some good points!
Trying to buy a plane ticket is one of the most difficult parts about the journey, besides picking a program and actually leaving. It is not only a lot of money, but it makes your trip abroad that much more real. When you buy the plane ticket, it is the first real thing that signifies that you are actually going to be leaving the country. Make sure you do it the right way!