If you mean the .410 pistol, in the US, these are classed as National Firearms Act weapons (similar to machine guns) and must be registered with the Federal BATFE. They are an "Any Other Weapon" and the registration tax is $5. If already registered, value may be from $500 to $1500, depending on condition. If the barrel is less than 18 inches, and it has not already BEEN registered, it cannot BE registered. As such, it is illegal to possess, and is worthless.
Ask a gunsmith for help
About $125, depending on condition.
No way to answer without a detailed description
H&R / Harrington & Richardson
Best left to a gunsmith
ABOUT $175-$200, depending on condition.
THESE WERE MADE BY H & R IN THE 1960 ERA
Around $100. Was one of my first guns
Harrington & Richardson (H&R) the maker of the Topper shotgun, was located in Worcester Mass.
It it has a 12" barrel, it must be registered with the Federal Government.
Your best bet is to contact H&R.
If you have the H&R .410 shot pistol, AND it is registered with the BATFE as an "Any Other Weapon", and is transferable, value is somewhere between $500 and $1100, depending on exact condition, barrel, etc. If not registered, it cannot be, and is basically valueless, with severe criminal penalties for possession.