With these tricks eBay will also lose money. Some time ago somebody in my family tried to buy from an eBay pet store and combined shipping didn't work by adding the items to the cart (although according to the seller all additional items after the first one should have been free). We contacted the seller but they replied after the 20% off was over and they had no clear idea what to do and basically told us to pick up the items from the store. Obviously we didn't go ahead with the purchase...