Basic Style Auction
Basic Style Auctions are auctions where the seller doesn't specify a hidden Reserve price, and the Starting Price offered is a price the Seller is willing to Sell at. So if a person places a bid in a Basic style auction, the Seller is obligated to sell at that price. Proxy bidding of the kind described by Reserve style auctions also occurs in Basic style auctions, except that the proxy bidding kicks in immediately. Again, Max bids are kept hidden while proxy bids placed by the computer and bids beaten by a proxy bid are displayed.

Dutch Style Auction
Dutch Auctions are initiated by a Seller that is auctioning two or more identical items. The dollar price you bid is for one of those items. The quantity you list is the number you are willing to buy, each at the price you have bid. For example, if you bid $5 and list a quantity of 3, you are offering to buy 3 for a total price of $15. There is no proxy bidding in a Dutch Auction, and the Starting Price offered is a price the Seller is willing to sell at. Dutch Auctions are run purely at the discretion of the Seller. So if you place a bid on an item with a given quantity, and someone later places a higher bid at a lower quantity, it is the choice of the Seller to whom he will award the items. Auction Arms is not responsible for the decisions of a Seller in a Dutch Auction! Sellers will be given a list of bidders and their bids at the conclusion of the auction. If you are a winner in a Dutch Auction, you will most likely be contacted by the Seller (as the Seller has an obvious interest in selling the item).

Best Offer Auction
A Best Offer Auction is an auction where the seller lists an item with a BuyItNow price, and buyers have the option of either buying the item using BuyItNow, or then can make the seller an offer. If a buyer makes an offer, the seller can either accept the offer, decline the offer, or decline all offers and lower his BuyItNow price. The seller has a limited amount of time to accept the buyers offer, or the offer automatically expires. That length of time is determined by the buyer when he posts his offer.

Proxy Bidding
Proxy bidding is an automatic feature of Basic and Reserve style auctions. When you place your max bid, if it's higher than the current high bid plus the bid increment, you're max bid will remain hidden until the computer needs it to outbid someone else. This process of outbidding someone until your max bid is met is called proxy bidding. Proxy bids can be placed on your behalf (until your max bid is reached) throughout the entire auction. Proxy bidding frees you from having to keep track of the auction, keeps your costs down by placing the minimum bid necessary to win, and prevents you from being outbid at the last minute, unless someone places a maximum bid that is higher than yours. You will be notified at any time that you've have been outbit, or at any time a proxy bid has been placed for you. In case of a tie for high bidder, the earlier bid takes precedence.