Once someone bids, the GIN can not be changed....Also, the lowest possible GIN amount is 2000....& as for an amount they go for, well... that all depends on how many ppl are bidding and how badly they need it. I've seen really cheap items go for over 5000 credits before & some really not so cheap items go for under3000 It just depends on what it's worth to the person bidding. ;-) Good Luck!