"eBay is a great way to acquire hard-to-find collectibles.
Trouble is, the best deals are often found in auctions that end in
the middle of the night. When that happens, the Biet-O-Zilla (BOZ)
extension for Firefox can help you, by tracking auctions and
scheduling bids in advance.
"You can install BOZ from its page on the official Mozilla
Addons site, but the version hosted there is outdated (release
0.4.6, from 2005). The latest version is 0.8.3, and is available
from the developer's BOZ Web site. BOZ is compatible with current,
2.0.0.x versions of Firefox..."