Most Internet auction sites require buyers and sellers to register and obtain a “user account name” (or “screen name”) and password before they can make bids or place items for bid. Passwords need to be kept confidential. If a user shares its password, another person could access the account and buy or sell items without the user's knowledge. That could damage the user's online reputation — and eventually, its bank account.
Many sellers set a time limit on bidding and, in some cases, a “reserve price” — the lowest price they will accept for an item. When the bidding closes at the scheduled time, the item is sold to the highest bidder. If no one bids at or above the reserve price, the auction closes without the item being sold.
Some auction sites allow sellers to set a price at which a buyer can purchase the item without competing with other bidders. A buyer can choose to purchase the item for the price the seller has set, without bidding.