"The Spanish Prisoner" (Steve Martin plays the lead, but it's not a comedy). David Mamet, so the lines are all intentionally delivered a little "over-the-top". Quirky little caper film that keeps you guessing until the end.
Not completely "low budget" but a cult (no pun intended) classic in my own mind: "Clue" (yes, based on the board game)
Was considered crap quality when it came out, and didn't make any money. That movie gets funnier every time I watch it. The ensemble casting could not have been better (Tim Curry, Madeline Kahn, Christopher Lloyd, Michael McKean, Martin Mull, etc.) the jokes could not have been more corny or better timed. In all honesty, I'm proud to say I could probably verbally follow along with every line of the movie. Many of those lines make regular appearances in my everyday banter. ("Split up?!" "One thing?" "I didn't do it!", etc....I could go on and on.)