EXP obtained during a WoE run has no bearing on what you get now. I've been in flux 9 with some LS mates, in which I got 10,070 exp, and one of them who got 4.8k got a scroll of blizzaja.....I, of course, got a some wyvern skin and other worthless crap.
The power to increase or reduce price lies inherently in the buyer. If you don't buy it, the people selling it won't keep paying the thousand's of gil to put it back up for the rejected amount.