Flying Cheap. Is It an Oxymoron?

There is not much to say because I think no matter how average price the ticket, we all wish it was cheaper....
I, for one, am no expert. I only fly about twice a year domestically, the other travels being road trips. That said, I do have a few tricks up my sleeve. 
 
First - Air Miles
       If you are going to use a card that gets air miles, get one that can be used on any airline with NO restriction. Citibank has such card.

It came in VERY handy!

Second - Search! 
       Try all the majors, orbitz, travelocity, kayak, etc. Then if you are not on a time crunch going or coming, priceline.com can deliver the goods.
       Or, have you considered smaller airlines that don't participate in those big search aggregates? Southwest is great with the "Ding!" service for last minute bargains and Allegiant Air has great prices but has limited routes. 
      However, owning our own business, I am always on the lookout for the best bargains, as it is still ultimately MY dime.  I stumbled across lastminute.com
I don't recommend waiting till the last minute, but sometimes it is unavoidable! I got very reasonable tickets from Denver to Baltimore for around $225 RT with a stop in D.C. No deplaning and tickets on other sites were $400-600 because it was within 2 weeks from departure. Again, it may not always work out, but worth the look! They have a US version and a UK one.

Third - Buddy Passes
      Totally depends on the airlines. Some run certain price per leg, like United. If you are going non-stop, decent prices and especially last minute. Others are flat rate. Some end up being same as buying ticket ahead of time, like when I flew from Denver to New Orleans. However, the buddy pass ended up cheaper because it cost nothing to change flight out when otherwise was around $100!

When flying overseas, there is all sorts of other factors, namely the countries going to/from. My sis found great deals last minute (unlike USA) because they would rather fill a flight. I have heard of other small airlines in Europe that you can get a ticket from country to country for next to nothing! $45 vs. $225 on major airline.

As with anything, do your research, it pays! And trek responsibly