Some of the best recent documentaries about the Nazis, their motivation, and the suffering they imposed are available for free from youtube.com. (The only down-side is that the documentaries are broken into segments that tend to be about 10 minutes long.) I would be happy to add other documentaries to this list. Just let me know what's available for free online.
I highly recommend the following:
The Nazis: A Warning From History BBC, part 1 (many interviews with German soldiers, politicians, and civilians about their attitudes toward the Nazis)
Auschwitz: The Nazis and the Final Solution BBC, part 1
(very well produced, includes re-enactments of key moments and interviews with former SS men who served at Auschwitz)
The Third Reich, part 1, from the History Channel (relies heavily on personal films and photographs)
The World at War: Inside the Third Reich, part 1 (Older BBC series, still compelling)