It costs precisely whatever people charge for it.
It is WORTH on the other hand, precisely what people with pay for it and not a penny more.
It is possible there is a large online auction site that may carry items such as you are trying to value. In fact I am positive there is and I'm sure the name of it will come to me in a moment if I just try to think hard enough. It's E- something, I think.
Well, anyway, as soon as you find that site you may discover they have a search facility. You could maybe use that to find items like the one you are interested in and check out how much items like that are actually seling for (Note: this may not be the price some people are asking for "buy it now" offers).
If only I could remember what that famous auction site is.
Anne Idiot, September 2015