Supposedly criminals will use ebay auctions as a way to fund illicit activities. The theory is that person a needs to pay person b for whatever illegal purpose. To not arouse suspicion person a sets up two ebay accounts and then bids again and again until the final sale price is roughly what they owed person b.
Personally I find that idea to be a bit too much tin foil hat nonsense for my tastes. But you do have to wonder. Looking at the bid history, it was two people in a bidding war the whole time. Egos got the best of them perhaps?