Documentarians spend most of their time digging up materials that few people know exist. They frequent basements and dark storage rooms, endure conversations with crazy collectors, and typically develop vitamin-d deficiency and light sensitivity in search of what they need.
Their reward for finding the material? A bill from the original creators (the ones who lost and forgot about the work in the first place) for the privilege of using it.
Ars Technica reports a story about filmmaker David Hoffman who had to pay $320,000 for materials used in a film about Sputnik hysteria that swept the US in the 1950s. Unfortunately, the best The History Channel would pay for the entire film is $200,000.