There are a few books that you can order online that will give you the approximate values, but they're not very accurate. The value depends highly on the condition. Watch a few saxophones on ebay to see what they are selling for. That should give you a pretty good idea what these horns will bring on the market. Typically, when I appraise a horn, I look to see what they are selling for on ebay, and then I add about 20% to that price, and that's what I consider the horn to be worth.