Creative magic can happen with limitations, one of the most interesting is a limitation many face every day. Money.
Primer - Fantastic movie, and $7,000 is going to be hard to beat.
Coherence for $50,000. One of the best sci-fi films in the last 10 years and yet could have been a play with two sets and no costume changes. THAT is writing.
Primer was going to be my offer as well but if you want to go a little more expensive then Monsters came in at under 500k and was mostly improvised and cobbled together.
Gone in 60 Seconds (1974)
I guess $150,000 isn’t exactly “no budget” but, my God, look at what Halicki managed to do with it. Likely the longest car chase in movie history involving 130 cars (90 of them wrecked) and clearing $40 million at the box office. You can just fast forward through the first half and it’s still the best auto-related film ever made.
Robert Rodriquez’s debut El Mariachi had a $7225 (1992) budget. Lots of bloopers left in as he couldn’t afford a do-over, which adds to the film’s charm.
Clerks.
A lot of it depends on the definition of low budget, as the OP runs from $7.5k to $200k. And there’s the difference between a good film and “good film for the budget”. Still, I think anything under quarter of a million has a shot at being considered “no budget” by modern (and the OPs) standards. Going by a few I’ve seen I’d include:
Mad God (2021)
The Man from Earth (2007)
Tetsuo: The Iron Man (1989)
Mad Max (1979)
Of course, we’re also leaving out inflation compensation and a ton of other factors, but that’s a quick list based on movies in my Plex Library. If we upped low/no budget to around $500k then it would expand a lot.
It Happened Here - Wikipedia 20,000$
Anti-fascist story of Nazis in England.
Night of the Living Dead - Wikipedia 100,000$
Somebody had to name it.
Primer is awesome.
Detour (1945) – Around $100,000
The Man from Planet X (1951) - $41,000
It Conquered the World (1956) - ?
Creation of the Humanoids (1962) - ?
Attack of the Robots (1966) - ?
Blood, Guts, Bullets and Octane (1998) - $7,300
Funny Ha Ha - $30,000
Meet the Parents (original 1992 version) - $100,000
One of the best movies I have seen regardless of budget is Open Water I couldn’t find a definitive budget though most report $130k (in 2003).
When looking at budgets you need to consider when it was made, after accouinting for inflation $20k in 1966 when it happened here was made is almost the same budget as $130k in 2003.
El Mariachi is probably my favourite. But I also thought of Crime Wave (made for $35,000 Canadian).
There’s a movie I’ve mentioned here before called Future '38. It purports to be (but isn’t) a recently rediscovered film from 1938 about someone travelling to the far future of 2018. A lot of the humor is in how it gets some predictions about the future almost right, but not quite.
I can’t find an actual budget figure for it, but it must have been pretty low. I don’t know if I’d call it a great movie, but from what they had to work with it’s good, smart, silly fun.
The Castle, Made in 11 days for $50,000 Australian dollars
I’m amazed anyone remembers this. I was going to mention it.
Also Luc Besson’s film Le Dernier Combat Made before he got into big-budget SF/fantasy blockbusters. It’s clearly shot on a budget, in black and white, and practically no dialogue. I can’t find the production cost, but it must be really low.
Jerome Bixby’s last film, The Man from Earth. Made in 2007 on a budget of $200,000 in eight days.
Bixby was the guy responsible for the story “It’s a GOOD Life”, made into one of the most famous Twilight Zone episodes. And for It! The Terror from Beyond Space*, 1from which Alien stole the plot. It’s one of the best SF movies from the 1950s. He also wrote the much-neglected The Lost Missile sand the Mummy-like Curse of the Faceless Man. He wrote four Star Trek TOS episodes and rewrote the script for Fantastic Voyage.
Offside, the Irani movie stealth-filmed by Jafar Panahi, who was recently released from jail (again) after being imprisoned for some other stealth-ish films. Offside cost about $2,500 in tape and editing, and it’s a good film.
Born Rich, being something like a student film made by the young man who is the heir of the Johnson & Johnson fortune. It features Ivanka Trump and his other friends.
Well worth your time.
The first Terrifier was shot for something like $60,000. IMHO, the production value is astonishing for that amount of money spent. The second one went for about $250,000, and still looks like it cost several times that.
Meet the Feebles, made by Peter Jackson before he came to the U.S. It’s kind of an R-rated version of the old Muppet Show; the backstage lives of a theater troupe of puppets. One of the most tasteless movies ever made. A friend of mine said that there’s not a single bodily fluid that isn’t involved at some point. If they weren’t puppets, the film would be a definite X rating.
Wikipedia lists the budget at $750,000.