Seems to me that Bartering might be the problem, Bartering seems to lower the price visually but not actually - making you think you have to pay less than you actually need to. I know I got the same bug when trying to buy something after getting Bartering anyway, haven't tested this out. Would be cool to know if bartering/treasure finding from luck affects the whole party or just the one character? Same goes for charisma and so on. Transparency would be nice - Bartering lowers the price of item X how much? And their disposition has affected the price x amount? Some people are against this kind of info, I am definitely for it!
