From Elite Minds:
The secret to winning eBay auctions is Snipe Bidding. Snipe Bidding means placing a bid in the final seconds of an auction. This technique allows the bidder to obtain the best price without bidding against non-serious bidders who run up the price. Sniping also allows bidders to win auctions that would otherwise be taken away by non-serious bidders who place high bids just for the thrill of winning.
You can't always be at your computer when an auction is about to end to place that critical bid. You may forget, you may not home or may be asleep. You need a Snipe-To-Win to place the bid for you automatically at exactly the right time. No worries about typo's or having to login and missing the end of the auction. If you place your bid early, some inexperienced user will come along and outbid you or run up the bid just for the thrill of bidding against someone.
Snipe bidding has both mathematical and psychological foundations. Even without the analysis, cool headed, experienced bidders have known for a long time that it is highly effective. Mathematicians have shown that Snipe bidding works statistically. Researchers at Seoul National University in Korea analyzed over a quarter of a million auctions and confirmed that Snipe bidding gives the best chance of winning. Bids placed early have less than a 50% chance of winning an auction. Snipe bids placed seconds before the end of an auction have the greatest percentage chance of winning an auction.