The extremely low budget film Primer is an excellent movie that shows what can be accomplished with $7,000 and an excellent script with a lot of hard work and dedication. The writer/ director/ actor/ producer/ jack of all trades who created this movie wanted to do a realistic movie about engineers and discoveries and what would happen if a time machine was invented.
The producer's take on the movie.
More about the story of the making of the movie at the official site.
One of the best reviews - Written about engineers... for engineers... by engineers.
In many ways this film is like Memento, another great movie, afterwards or with repeat viewings you puzzle out the timeline. Or in this case timelines - time machines complicate things. Another set of possible time lines.
Other somewhat related films if you like this are Donnie Darko and Eternal Sunshine of the Spotless Mind.
In concept this is most like The Man Who Folded Himself, which is a time travel book not for everyone. I would recommend The Best Time Travel Stories of the Twentieth Century and Replay available on the same page.
Update: This also looks similar to Timecrimes, a new Spanish thriller opening now.