i used hotwire to purchase tix for three different trips.

colorado springs to orlando for $237 ($495 through NWA)
amarillo to birmingham for $208 (most tix are above $350)
shreveport to amarillo for a measly $141

bear in mind that tix do NOT accrue frequent flier miles, but all in all hotwire is the BEST place to find the cheapest airfare as long as you do not mind having no control over flight times. i'm flexible if it's going to be cheap.