A lot of useful info, typically sold on eBay http://www.floodle.net/extra/ebayinfo/index.html
here . Basically, this website got all the stuff some "sellers" on eBay charging for (and some guys are really paying for it! never understood it...)
In addition to stuff listed above, I am always amused by people selling "quality user manuals" as PDF downloads. Especially now when most companies allow anyone download these from their websites for free. Yet there eBay auctions on it... I simply don't get it.