10-100 USD maybe
10-500 USD or so depending on the specifics.
100 or so
50-400
40-150
No such weapon
Gun shop, gun show, Egunparts
Condition is everything when valuating firearms. An Hopkins and Allen .32 cal. hand gun can range between $45 in Poor condition to $300 in exceptional condition for a scarce/rare model.
0-70 USD or so
20-80 USD or so
100-435 USD
Depending on EXACTLY what it is, 25-2500 USD or more.
Blue Book of Gun Values is a place to start