@PiHu just google it or look on eBay to see how much they sell for. I don't know if there really are websites for this. You can have a look and let us know if there is such a thing ;)
@der_Don uff... Source = Google prices? Sounds to me like an investment where you have to spend 110% of your time on forums, similar to Lego's, antique etc. How do you store the bottles?