Okay. So what if the vocals sound similar to that of in Metallica's songs? Saying they suck and they're a rip-off is just giving them free publicity, and you're being stupid. If you receive 'fun' or cure boredom by saying a band's vocalist sounds like another band's, your life must be pretty damn silly.

To the point of the topic: I'd recommend trying eBay or some other auction site, because if it's a rare demo CD, those things go on auction sites. However, you'll need alot of cash - think of rare CD's as antiques, only different and less pricy.