Not sure if this is a repost but there are some cool Metal auctions from Jon Zazula's personal collection. The Anthrax stuff seems a little pricey, but Metallica's first demo has got to have some collectible value.
http://search.liveauctions.ebay.com...d=6435&lc=1&isl=0&ccn=Entertainment&ahid=3052
http://search.liveauctions.ebay.com...d=6435&lc=1&isl=0&ccn=Entertainment&ahid=3052