A FlyerTalk Posting Legend
Join Date: Jul 2002
Location: MCI
Programs: AA Gold 1MM, AS MVP, UA Silver, WN A-List, Marriott LT Titanium, HH Diamond
Posts: 53,012
Not in the realm of "world's cheapest", but possibly up there in the annals of unusual fares: about 3 years ago (right at the tail end of TWA's existence), I booked a walk-up one-way fare MCI-STL-TPA for $62 all inclusive. I think the base fare was about $40. Just this year, I got a one-way ticket on Delta MCI-CVG-IND for something like $42 - a base fare of $27.
I do not believe that either was a "mistake" fare, however I don't believe anything is truly a "mistake" fare.