Y-Ups are special codes on first-class airfare that indicate that the seat can be assigned to those looking to upgrade from economy. To find one of these fares, go to your preferred airline's Web site. Search the first-class seats on the flight you want to take. If any of those seats are tagged to a code like Q***UP, write down that code. Then, search for an upgradeable coach seat (some airlines don't allow upgrades for super-cheap coach fares), and write down the code for that seat, too. Finally, call the airline--they'll usually waive the telephone service fee for frequent fliers, if you ask--and use both codes to request that your coach seat be upgraded to the first-class seat. For the price of coach, of course.