Impossible to value without knowing who made it and what shape it is in.
10-100 usd
About $375-$450, depending on condition.
100-500 USD
@40-100 or so.
25-125 USD depending on condition
100-1000 or so depending on EXACTLY what you have.
$100-$150
1874 or 1875. IMHO, worth spending the money to get a letter from Colt on it.
475
100 USD or so
100-300 depending on specifics
$150-$300, depending on type of metal and condition.