It helps neither the bidders or yourself. Contact the highest bidder immediately after the auction ends. You will find their contact information both in your email and by clicking the Closed Auctions link. After the transaction has been completed, be sure to leave feedback on the buyer. And remember that they'll be doing the same for you.
Sellers have the option to place a reserve on any item they are selling.
A reserve is a price set by the seller below which they will not sell the item. If no bid is placed which meets or exceeds this amount, the seller retains ownership. Reserve prices are intended to protect the seller from unreasonable losses. There is no fee for bidding and buying. The only costs incurred are the direct costs of your winning bid and any related handling and shipping charges.