Check out your local auctioneers. You can often pick up plenty of bargains, which can be sold on eBay.
As an example of what you might find, I'll tell you that I'm posting this message with a fairly modern PC, with loads of memory, a fast processor, separate good quality sound and video cards, a CD drive and separate DVD rewriter. It came with a clean unregistered installation of XP Pro and all the usual accessories (including a flat screen monitor). I bought it at a local auction for just £15!
Auction rooms vary a great deal. I recommend looking in your local Yellow Pages for auctioneers who do house clearances. (That's where you'll find some of the best bargains).
Alternatively you could try one of the auction rooms which specialise in selling trade stocks. (They're often from bankrupt businesses). For example, here's what TLH (in Oldham) were selling earlier today:
http://www.tlhauction...es/catalogues/cat.pdf
Chris