Check Kayak first – I really like this website because it compares all the prices from many of the airlines and travel websites (like Expedia and Travelocity). I can also set a price alert to know when the price goes down. This is where I start my search. It gives me a general idea of the cost and what airlines fly to my destination. (This website doesn’t include every airlines that may fly to your destination.)
Check prices after business hours – It seems that the prices change during the evening, late night, or weekend hours. This may or may not always be the case but it might help you find a better price than what you will find during the day.
Check the airlines website directly – Sometimes if you go directly to the airlines you can get a better price. This isn’t always the case, I once booked a Delta Flight on Expedia.com and it was cheaper than Delta.com.
Sign up for email newsletters from the airlines – You will get emails from them when they are having a sale. Sometimes they will also include a coupon code. (The coupon codes are generally in the newsletters from smaller airlines.)
Check out the airport and see what airlines fly in and out of that airport – I like to use the information I find at Flightstats. I can pick “By Airport” and pick today or tomorrow to see all the airlines that fly in and out of that airport. With this information I can check out the fares for smaller airlines that may fly to that airport.
See if there is another airport in the area – My main airport is Tampa International Airport, but St Pete/Clearwater International Airport is just 14 miles away and has a lot of cheaper airlines that fly into smaller cities. This may not only be a cheaper option but an easier option.
Be Flexible – If you are able to be a little flexible when traveling you could save as much as $100 on a flight!
Know the extra fees – Will you have to pay for luggage? What the maximum weight of the luggage? Will you have to pay for your seat assignment or carry on luggage? After you factor in all these costs you may pay more than another airline.
Join their Frequent Flier Program – Even if you don’t travel that often, I would suggest you join this free program. Your miles will add up fast. Some airlines even let you use your miles for 1-way tickets. They also have many ways you can earn miles – by renting cars, hotel stays, or online shopping.
Book through Cash Back sites like Ebates and Shop at Home – These sites will give you $5 for joining and either a flat payment per flight or a percentage back on other travel needs. Every little bit helps!