Collectiblend – Great website for vintage camera price check
This is super website that brings together prices for film cameras. Great place to see how much is your camera worth or how much is worth camera you want to buy. www.collectiblend.com
Prices for recent 35mm SLR are a bit too high, because they are from auction houses not eBay, prices in eBay are low because of many similar cameras sold. But for older or more rare models they are quite good. You can also check their great forum for recent purchase prices.
They even have camera manufacturer tree of some of camera maker, how they advanced, which went down which were renamed or sold – http://collectiblend.com/Cameras/Family-Tree/Camera-Manufacturing-Companies-Family-Tree-v1.3.pdf