20-80 USD or so
100 or so
50-400
No such weapon
0-70 USD or so
100-435 USD
Depending on EXACTLY what it is, 25-2500 USD or more.
10-100 USD maybe
Blue Book of Gun Values is a place to start
Gun shows, gun shops, want ads,
25-125 usd
25-100 USD without more of a description
10-1000 USD or more depending on specifics.