You need to give the make, model, condition, and, on some guns, serial no. before a value can be estimated.
Best advice is to check if your local library has a reasonably current copy of "The Blue Book of Gun Values" and check in there. Also note the section in the front of the book for estimating the percent finish remaining. Many people are surprised to learn that the gun they thought was "almost like new" is a 90% gun.