From Sparetime Software:
Ebay Bargin Hunter is a bargain hunter program that searches eBay for items you specify at a price you're willing to pay. It runs in the background and periodically searches eBay for a good bargain so you don?t have to. Simply go to the eBay Web site and search for items you're interested in. Click the Bargin Hunter button on Internet Explorer or the BarginHunter icon on your desktop and save the URL that eBay returns. Specify your price and time limit. Save as many searches as you want. There's no limit. It will notify you when a bargain is detected and allow you to view the auction.