Bids on LO work pretty good and I know people who upgraded from PE for only $250 (at least they used to, dont have any recent experience) PS works in airport at check in but CASH only, I don't think they have a set price but rather ask according to demand, I wanted to upgrade before RH on a busy flight and they asked $800
LY also allows upgrade-on-board from what I recall,
does anyone know how much?