Just a correction (for the second time), those are bugged items. Even non-hackers (aka all players) could dupe those if they knew the process (I think it has something to do with mailing). But anyway, Ntreev already fixed the bug more than a week ago but sadly some players have already farmed some rares. Maybe, it would (probably) take 6months to a year for the economy to go to normal. (overpriced rare items= spec = 6million kkkkkkk).
and WTB> 2 more servers. -_-
Edit: I will take it back. It seems few people were selling rares from 20k to 1 pang. Yeah, it seems the bug is still not totally fixed, or probably a new hack, or probably some players farmed thousands of those rares, only those greedy b'tards know.