What is the value of a smith and Wesson 9mm 39-2 with serial number A321036?

You have only provided a generic description. Trying to put a value on anything with just this limited information provided is difficult. Value depends on a combination of many factors. Without a detailed description to include, finish, barrel length, overall condition, stock material, sights, box, original paperwork and any accessories, only a general estimate can be given. This weapon could be in the 100-550 USD price range.