A bidder is someone who offers to pay a certain amount of money for something, usually at an auction or in a competitive situation. When valuable items go up for sale at an auction house, bidders raise their hands or call out increasing prices, each trying to offer more than the others. The highest bidder wins the item and pays what they offered.

You might encounter bidding when a school auctions off donated items at a fundraiser, or when construction companies submit bids (their proposed prices) to build a new library. In these situations, each bidder is essentially saying, “I'll do this work for this amount” or “I'll pay this much for that item.”

At an auction, inexperienced bidders sometimes get caught up in the excitement and pay more than an item is worth. Successful bidders stay calm, set a maximum price beforehand, and try to stick to it.