Standard eBay auctions use a hidden proxy bidding system.
The “hidden” component of hidden proxy auctions means that the prices of all bids are hidden until the auction closes.
The “proxy” component of hidden proxy auctions means that you can safely bid the maximum amount you are willing to pay for a sale item, but you will only have to pay the minimum amount necessary to win the auction.
For example, if you see an antique pistol holster you wish to bid on, but you are only willing to spend $200 on, you can safely bid $200 for the holster. If the 2nd place bid is for $50, you would win the auction and only pay $50 plus a small increment. You would get your $200 holster for only $51!
Dutch eBay Auctions
Dutch eBay Auctions are used by sellers who have many identical items which they wish to sell.
Bidding in Dutch eBay Auctions is neither hidden nor proxied.
In a Dutch eBay Auction, all bids are made public.
In a Dutch eBay Auction, eBay does not proxy bid for buyers. Each buyer pays the amount bid by the winning bidder.
For example, if an eBay seller is listing 5 NRA safety videos and you bid $15, your $15 bid is then made public. The 5 highest bidders at the end of the auction will win a video — at the price of the lowest winning bid. If the lowest winning bid is $8, the top five bidders will win the videos at $8.
For more information on Dutch eBay Auctions, read eBay Help: Dutch Auction.