Because film photography has decreased in popularity, many old film cameras are being sold at garage sales, thrift stores, pawn shops and antique shops. Finding the approximate value of those cameras is simply a matter of checking and comparing resale values on a number of websites.
Establish the camera make and model. This can be a little tricky. Some manufacturers changed features in particular model lines over time. The best way to establish the exact make and model is to find a website that lists serial numbers, and their corresponding manufacturing dates and feature sets.
Do an eBay search for your make and model of camera. Price depends heavily on the condition of the camera, so keep this in mind when reviewing sale prices on eBay. EBay prices also tend to be lower than retail prices on commercial websites or at retail stores that carry used cameras.
Search the Used Store at B & H Photo Video. Consider this price to be the highest possible price that you can get for a camera on the open market.
Search the Adorama used-equipment section. In general, Adorama is a good comparison for a mid to high price for a private sale.
Look up the camera make and model at KEH. KEH will give you a low to mid-priced estimate of how much your camera could sell for in a private sale. Remember, condition of the equipment is very important.
Compare the prices from the aforementioned websites.
Not all sites will list all possible cameras. Check each site, and use an average of the prices as a realistic sale price. If possible, have the camera checked by a qualified technician, and use his analysis of condition when trying to price your camera.
The value of many very good film cameras, especially 35mm cameras, has dropped dramatically as digital has become popular. The value of other older cameras that may not be in cosmetically good condition has increased as collectors and photographers realize that these cameras are becoming scarcer.