I often rely on state archives and local historical societies for genealogical and heir research. More of these research projects have landed on my doorstep related to Quiet Title actions. Some of the property ownership information is 100 years old and the living descendants need to be traced. State archives and town or county historical societies have gathered an enormous number of documentary resources, some are posted at their Internet sites, and have in house researchers that can assist you for free or at a very low cost.
The Georgia State Archive, for example, has Ask An Archivist, an email query system for research questions and free lookups in their records.
The Missouri Secretary of State is gradually adding more records to their Cororner’s Inquest Database.
Family Tree Magazine has a resource list of the best Internet sites for genealogical research.