It all depends. Most "used" S&W revolvers do not bring as much as new "retail" prices. Some older pre-lock guns are more scarce than others, and may command a premium. Some guns are just not popular and do not command any premium. Condition is a big factor, and any "collectable" specimen will bring less and less as the % of original finish disappears. You should consult a good pricing book, such as the Standard Catalog of Firearms, or the Blue Book. Review the pictures of the conditions represented, then look up the actual model and apply the condition column. Keep in mind these books are only a guide and different parts of the country the prices may vary also. If you have a couple of particular S&W you want to get an est. value on, look here:
To IDENTIFY your Gun > this is a guide to identify and value and what will help us do it.