A shotgun.
A shotgun made for Smith and Wesson, sold under the Smith and Wesson name.
Seldom exceed 300 USD
$650-$1000 used
Standard Catalog of Smith and Wesson, 3rd, ed., by Supica and Nahas can answer your question.
It will be marked on the barrel
Needs to be examined by a gunsmith.
Impossible to answer without more details.
50-360 USD or so
NO sn data for this S&W
100-400 USD
50-450 usd