If you don't have an owner's manual, find a gunsmith and ask for help
25-56 USD
Could be German, Italian or US
$25-$75
25-160 USD depending on specifics
50-126
FIE stands for Firearms Import & Export. Cheap guns imported from West Germany, Italy, and manufactured later in Miami, Fl. E-15 is a ruger knock-off.
FIE was the company that imported these into the US. They were made in Brescia Italy, POSSIBLY by the Tanfoglio Company. FIE is no longer in business- the E-15 single action revolvers seemed to be from the 1960s-1970s. They do not have a high value. Some repair parts are available from gunpartscorp.com.
No way to tell from just the sn. Provide a detailed description of all markings.
Try internet auctions, pawn shops, gun shops, gun shows, want ads.
E-gunparts
Try e-gunparts.com
Try e-gunparts.com