After thinking about Quest for Fire, I realize that another of the most formative movies for me was 1984's The Iceman. The body of a prehistoric man was found frozen in ice, but still alive. He's placed in a zoo-like containment room at an arctic research facility (filmed in Churchill Manitoba, no less) where he can be studied. Another fascinating movie, not because of special effects or high budget, but because of story. Any movie involving a prehistoric man singing along to Neil Young has to be OK...
The movie was about alienation. About belonging. About finding out who you are, and where you need to be. It was about human nature. It was about fear. And mythology. It was about standing up for what you believe in. And also a little about anthropology.
I remember watching and rewatching this movie several times, mesmerized by the details. And knowing that a high budget version of the movie would have lost almost everything that made this movie great.