Actually I got a last minute upgrade dirt cheap!
When I checked in online I was given the option to upgrade to F class for $450. Yea right. Anyone who would pay that for a 2 hr flight needs to get their head examined.
When I got to the airport and checked in, the gate agent told me there was 1 F class seat avail and no one had bought it/shown up for it. Did I want it... $30. For $30 you bet I wanted it! So the airline got $30 ontop of my original fare instead of getting $0. Smart move.