The US National Security Archive
Access 
The NSA operates as a public service, thus its vast content is free and open to any user, including free retrieval and pdf file downloading, with a useful collection of links pointing to other resources and material for further information.
Fee Policy 
Funded by private foundations and the George Washington University, the whole archive is able to operate as a public service, thus its content is free and open to any user
Free Retrieved Material
Since this site collects and publishes declassified documents, its policy is to make them directly and fully available to any user, who can also receive updates via e-mail
Linking Richness
Throughout the site, the Archive provides a rich and useful collection of links pointing to other resources and material for further information