1. First class for less
If you're looking to fly in style - either by buying a first-class seat for a coach price or by identifying specific flights where the odds of landing upgrades are unusually high - head to ExpertFlyer.com.
For $5 a month, the site offers the complete, up-to-date inventory of unsold seats for most major airlines, including unpublicized first-class tickets for the price of a last-minute coach fare. While ExpertFlyer can't book your seat, it does give you all the information you need to purchase a discounted ticket directly from the airline.
That one extra step isn't so bad when you consider the savings: A recent ExpertFlyer search returned a first-class fare of $779 for a transcontinental flight on United while United.com was quoting $2,335 for the same seat.