And what do you suggest to stop this? Anyone could do this behavior on any type of auctions - ebay etc but there's nothing that can really be done about it nor is it the staff's problem to police.
Well, ebay is a very different case so I don't think that I should comment on that one.
As of my suggestion, newbies (and maybe Jr. Members too) could only post new topics on the board, and not reply with bids. This way users wouldn't create new accounts just to boost their auction.
Furthermore, some IP restrictions could also work. I know that this is easily bypassed but it's easily implemented and surely better than nothing.