More information is needed to identify the manufacturer of this pistol.
About $25.
$6
6-8
25-75
50-100 or so
There is no Remington Model 6 pistol, there has been however cases however of Remington Model 6 rifles converted to pistols by gun or "home" smiths. NOT Remington. As such the value is whatever someone will pay, but generally not much.
10-100 usd
No such model in the Ruger line.
50-100 or so
Depends on condition, accessories, etc. Best estimate would be 400-600
100-300 or so
100-1000 depending on specifics
About $25.
You have falied to described it in enough detail to give a good answer. Broad range would be 250-550
$6
6-8
100-500 or so