From the C-SPAN Video Library About page:
"Every C-SPAN program aired since 1987, now totaling over 160,000 hours, is contained in the C-SPAN Archives and immediately accessible through the database and electronic archival systems developed and maintained by the C-SPAN Archives....All C-SPAN programs since 1993 are digital and can be viewed online for free .Duplicate copies of programs that have aired since 1987 can be obtained and used for education, research, review or home viewing purposes. Proceeds from the sale of these programs help support the operation of the Archives." Read more....