There are numerous royalty free stock footage websites where a one off fee is paid for an unlimited use licence. Here is one example http://www.artbeats.com
There are also similar sites for music. Here's a good one http://www.music2license.com - a one off fee of 40 grants the licensee an unlimited, worldwide synchronisation licence.
Undercurrents is an award winning alternative news service producing videos of people taking inspiring actions. http://www.undercurrents.org