With WP Auctions 4.0 you now have the option to hold auctions in any of the 3 bidding engines that come with the plugin.
1. Simple Bidding
This is the simplest bidding engine. Here what you bid is what you get. So if a bidders bids $10, the current bid is $10. If they bid $42.76 the current bid is $42.76. When used in conjunction with the minimum bid increment the bid place will have to exceed the increment amount set.
2. Proxy Bidding
Our default engine, proxy bidding enables a user to set a Maximum Bid till which they are protected from being outbid. So if Bidder A places a Maximum Bid of $20 and Bidder B comes along to try and outbid A, A will be protected till B outbids A over $20. When used together with the minimum bid increment setting the increment amount will have to be met for any new bids, but it does not invalidate the proxy Maximum Bid set by Bidder A.
3. Reverse Bidding
This bidding engine enables you to hold auctions that go down in price. If an auction starts at $50 and someone is willing to bid $49 they can do so and so on and so forth until the lowest price wins. This type of engine is usually used for contract bidding and items that are serviceable in nature.