How or where can I find pipe values?

[Zoomschwortz]

Well, lets take Ebay for instance.

If I see a pipe made somewhere in the 50's that is in nice shape, how do I place a value on it?

Another case, I bought a beautiful freestanding J shaped Giorgio Orsini with silver on the stem and on the top of the bowl. The fit and finish is very nice and it smokes great.

I bought it in Munich in 2007, don't remember what I paid for it, but I believe it was somewhere in the 150-250 Euro range.

Did I get a good deal or did I get ripped off?

Where would I go to find out?

Thanks.
Ken