Value of ANY gun is based on make, model, and condition. You gave us one of the 3 things we need. There were several models of revolver made by Harrington & Richardson over a great many years. Values could range from $10 to $400.
200 USD
25-125
25-130 USD or so
Best left to a gunsmith.
H&R makes a 22lr 9 shot revolver, Model 904
Depending on heavily on condition, anywhere from $75-$225 roughly.
I own one and they are worth around a 100 dollars
Depending on condition 25-150 USD
Winchester magnum rimfire
50-125
50-90 yrs
H&R made thousands of revolvers.