5-80 uSD or so
Howard Arms was a trade name used by Sears Roebuck on revolvers made by their subsidiary company, Meriden Firearms Co., from about 1905 to 1915. The only "model" designation would be the caliber, .38 or .32.
Howard Arms was a name used by the Meriden Arms company from around 1905 to 1915. There are no records available to give you a better date. Their value is around $100.
10-60 usd
Look under Iver Johnson Arms and Cycle Company. Their hammerless revolver was sold under several trade names, including US Revolver Co. You can probably find one for sale on one of the online auction sites.
50 or so
The name of your revolver is incomplete. Please repost with full name.
No published sn data.
charter arms pistols are medium quailty and sell around $200 max
About $200, depending on model, finish, and condition.
75-275 or so
About $200, depending on condition and exact model.