When I first saw Clerks I thought, "wow, look what you can do with $30,000."
Tonight I watched Primer, which cost $7,000 and is all around a much more impressive film. The plot is incomprehensibly dense at the end, but the filmmaking is deft and the quality high. I hope Shane Carruth -- the writer/director/lead actor -- is able to really put a lot more into his next project.
I won't even try to get into what the film is about except to say that it's a movie with no special effects about time travel. Reminded me of Pi, but without being so aggressively artistic. The way in which the pace and style captures the life of engineers and techies at work is really quite endearing (Carruth was really an engineer apparently) and the manner in which the whole thing plays out is reminiscent of the work of the great Russian director Andrei Tarkovsky.
The film is about 1:15, and you can get it off Netflix. I liked it enough to look for the filmmaker's email in the WHOIS record for the movie's website and send fan mail. Strongly recommend.