Even if you're buying for the whole family, start by searching for the price of one ticket. Sometimes you'll be able to save money on one or two tickets and then have to pay a higher price for the rest.

Ed Jones/AFP Photo
An aircraft takes off from Hong Kong international airport on June 5. Citing an increase in air traffic demand on the back of strong economic growth in Asia, the city's Airport Authority said it had to find ways to increase the capacity of the airport because current facilities were expected to be saturated by 2020. A proposed third runway would enable the airport to handle a maximum of 620,000 flights a year, the authority said, though environmental groups have expressed concern over the plan which they say would threaten an area popular with endangered Chinese white dolphins.