I own a Rare Video Price Guide from around the time when VHS was at it's glorious peak (before DVD completely dominated the market), so if anybody would like to know how much their tape is, just drop me an email to viva@vivavhs.co.uk and i'll be more than happy to check the book and email you back with it's worth. The price will have dropped in most cases but for some the prices are still rising, especially if you happen to own any of the Video Nasty or DPP titles.
All I require from you is the name of the film, the studio that released it and the serial code from the spine of the case. Who knows, I may even make you an offer...