50-100 USD
Not more than 100 if that
Impossible to answer without a detailed description
50-75 USD
$50-$85, depending on condition
75-125
Depends on who shot it and or who was killed with it!
Depending on condition, $25-$100.
With soap and water.
100-1000 or more
We need more information to identify the model. Colt's original single-shot derringers were in .41 caliber, not .22. They did make small single-shot derringers in the 1960's in .22 cal, but they did not have the markings you describe. www.countrygunsmith.net
About $175.00 for single shot models and about $200.00 for repeater models