In the first-price auction model (also known as an English auction) the bidders pay exactly what they bid. It’s a model used in art auctions.
For example: Bidder A bids $4.00, Bidder B bids $4.50 and Bidder C bids $4.20.
Bidder B wins and pays $4.50. The first-price auction requires the winner to pay the full price they bid.
