Well, I don't know whether anyone find this interesting, but I just bought Crystal Ball from Rokkaku for about 200-400 potch and brought it to Kobold Village, then for some reason the price of Crystal Ball is 20988 potch. Usually I sell Crystal Ball for about 2300, 4600 or 6000 potch at max in Kobold Village. Yet this time round it amassed 20000 potch. I don't know whether or not this is a glitch or it has something to do with buying Crystal Ball from Rokkaku specifically and selling it to Kobold Village, cause this is the first time I bought it from Rokkaku. Usually I buy it from Forest Village or South Window. I attached the screenshot.

My guess is that there have been no crystal balls in kobold village and there has been a rumour that you can sell them there for a high price. (do rumours exist in SII?).. that would explain it.

Sometimes the prices skyrocket, if there are needs for a certain item. It's unusual high for a crystal ball, but I don't think it is a glitch.

Kobolds really love Crystal Balls (also the Nekobolds) so..because it's in demand, it costs high! Those beasts really are weird!
waah racism! lol.

It's already established that Crystal Balls sell for lots in Kobold Village. =\

Crystal Balls normally sell for only up to 7000 potch. 20000 is clearly way out of the norm. I can't offer an explanation other than the obvious ones already mentioned in this thread, which was already pointed out by the TS anyway.

It's probably a glitch, but I don't really trade that much. I only use like two Ancient Texts and two Crystal Balls for Gordon's requirement.