The article explains why online auctions are used to sell new items and how they affect prices. Buyers bid more as the deadline nears, and sellers choose between auctions and fixed prices. The study shows that prices vary even for identical items, and buyers bid more in each auction. Data from eBay supports these findings. Retail auctions can increase overall welfare by 1.8% if fees cover costs, but decrease welfare by 2.3% if fees are pure profit.