Can't be answered witout knoiwng all details.
10-100 USD or so
$100, more or less
50-100 USD
No such maker. However, there is a firm called Harrington and Richardson and they did make pistols in 38.
Not enough information provided. Need description of the revolver, including any and all markings on barrel and receiver, type of action and model if available.
There were dozens of different top break models made by Harrington & Richardson. Your best bet will be a search engine, such as Google. Select IMAGES, then Harrington & Richardson. The link below takes you to ONE such image- a nickel plated, top break 38 S&W hammerless revolver by H&R.
10-100 usd
25-75 USD or so
25-75 USD
May not be marked, depending on age.
50-100 USD
Depending on condition, $30-$120