ponchobelt said:
you get a friend or a couple of them to bid on the item to drive the price right up which then either makes other people bid as they see it is going for a lot and think it must be worth bidding on OR you get a mate to bid on it to drive up an original bidders maximum bid.
If they win the item then the seller hasn't really lost out as they can then just re-list it in a few weeks and then hope that people don't make the connection!
I've never done this ( :? ) but I did read somewhere that some guy went to prison for a few weeks (months maybe?) after being found guilty of doing this.