Knowing when to buy your ticket may save you money and help you smile when you travel.

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So, you're planning a vacation, but like so many who have suffered through recent economic misery, you don't have a bottomless wallet. Well, you're in luck. You've come to the right place for some help finding cheap airfare.

The cost of travel is going up, and it's not just about the expense of buying a ticket. With airlines struggling to operate due to rising fuel prices and bad management over the past several years, passengers are bearing the brunt of increased costs associated with air travel. Airlines used to serve complimentary soft drinks and meals, but have now turned to charging for such amenities.

In addition, even though airlines have been charging for baggage for some time now, airlines such as Spirit are starting to charge for carry-ons [source: Croghan]. But not every carrier is willing to go to such lengths to make money. That's why you can avoid these costs by packing light and not delving into such luxuries as dining aboard the once-friendly skies.

If you really want to save money, you'll have to take these expenses into consideration and shop around for reasonable fares. Airfare can more than double in cost, depending on when you fly. It helps to be flexible.

This article will give you the tools you need to plan your vacation efficiently, starting with the airfare. Let's begin with some empirical data. See what's revealed after crunching a bunch of numbers for flights headed to Cancun, Mexico.