5-6 shot is best but 7 1/2 will work but not recommended
50 USD
50-100 USD
20-200 usd
50-100 USD
50-110 or so
Your best source of gun values is Fjestad's "Blue Book of Gun Values". You can usually find a copy at larger libraries.
100-400 USD
10-350 USD or so
10-150 USD or so
Anywere from $75 to $150 used. Depending on condition.
100-500 dollars
Double barrel?? Single shot?? More info. is needed.