RLG News and ArchiveGrid
Thousands of libraries, museums, and archives have contributed nearly a million collection descriptions to ArchiveGrid. Researchers searching ArchiveGrid can learn about the many items in each of these collections, contact archives to arrange a visit to examine materials, and order copies.The contributor list crosses many subject disciplines. I'm not sure what the subscription price will be, I could not find any details on the RLG Price List.
ArchiveGrid is available to both individuals and institutions free of charge through May 31st. If additional grants funds or sponsorship are obtained, ArchiveGrid will remain free of charge; otherwise subscriptions will be available for institutions and individuals alike.