Impossible to value without a detailed description of all features and overall condition.
I assume your single action is pre-war ? If so, then made about 1907. As to the caliber, check markings on barrel. that should give the caliber.......
You will need a professional appraisal.
A pistol is a single hand firearm with a short barrel.
any single or double action semi-automatic pistol listed as a 40 caliber pistol...............
a gun lol
Need a better description. Is it a pistol or revolver? What are the markings on the barrel or slide? is it a single action(cowboy gun)? is a double action(police gun)?
Which model? sales@countrygunsmith.net
Depending on condition, $25-$100.
A .44 caliber derringer.A small pistol called a Philadelphia Derringer.
Fifty dollars, give or take $50.
Single barrel, under $100. Double-barrel up to $200 unless heavily ornamented.
Impossible to answer without a detailed description