We are creating a reverse auction for IT peripheral hardware and was hoping to get some feedback from those of you who have done it best. I was wondering if anyone had experience running an auction that leads to a cost plus (cost + margin) cost strucutre. The bids will come in as an actual price but we were thinking of making that the baseline for the cost plus margin going forward. The issue is that not all items will have a similar margin so I don't want to leave money on the table. Any tips would be greatly appreciated.