This film initially cost $7000 to make. Director Robert Rodriguez raised $3,000 of the $7,000 by volunteering to be a human "laboratory rat". He was used to test a cholesterol reducing drug. Paid $100 a day for 30 days, he wrote most of the script while locked in the lab. Peter Marquardt was a fellow "rat", but could not speak Spanish. He delivered his lines from card held in his hand or out of shot. Most of the $7,000 was spent on film for the camera. The version seen in most cinemas has had approximately $1 million of post-production work and promotion behind it.
Sound was recorded with an ordinary cassette recorder and mike. The sequence with the pit bull terrier was shot specifically so that Robert Rodriguez could synchronize the sound with the picture later.
Robert Rodriguez was producer, director, writer, special-effect man, etc, the only job he didn't do was act, as there would be no one else to operate the camera.
The guns which were borrowed from the local police station had a drawback, blanks could only be fired one at a time because they jammed the gun. Robert Rodriguez fixed this in editing by "double-cutting" the gun firing then cutting to the bad guys getting squibbed with machine gun sound effects.
In his book "Rebel Without a Crew", Robert Rodriguez explains that the gangsters' peculiar names are meant as a joke: they are all nicknames the characters had as children but never outgrew. As such they are named La Palma (Spanish for "palm"); Azul ("blue"); Pepino ("cucumber"); Moco ("booger").
In addition to the subtitled version, Columbia had an English-dubbed version prepared for release on home video. According to director Robert Rodriguez, the dubbing job cost more than he spent to shoot the original film.
For much of the outdoor filming Robert Rodriguez was down the street from the Mariachi. People walking by did not see him, just the man walking down the street with a machine gun.
To warn people he was filming, Robert Rodriguez would place a sign at the end of the street he was shooting on. He wrote it in English so no one would understand what it meant.
The hotel owner and bartender were both local newscasters who were talking negatively about the movie. In order to get them to stop Robert Rodriguez gave both of them small parts in the movie.
Many of the edits were necessitated by Robert Rodriguez's frugal nature. Any time the actors made some progress through a scene and then messed up, Robert Rodriguez cut to a different angle right before the mistake rather than re-shoot the whole scene.
Many of the exterior scenes were shot on the same two blocks to avoid using up too much money on gas. This is most obvious in the first chase scene, when the Mariachi supposedly runs away from the hotel he's staying in, yet it can be seen just over his shoulder soon afterward.
The title was not translated for the American release, as it was felt not many people would be interested in an action film titled "The Guitar Player".
Robert Rodriguez's original budget projection was $9,000. He brought his film in on time and under budget, mainly by shooting only one take for every scene, thereby saving on film.
To record the dialog and sound, the actors would do a shot for the camera and then immediately repeat their dialog and actions for the microphone. For the most part, the actors were able to do their dialog with the same words and pacing that would allow the two elements to appear to be in sync.
While the production budget for the film was $7,000, Robert Rodriguez estimated that if he didn't have to pay for film, processing and telecine costs, it would have only cost $600.
The trivia items below may give away important plot points.
Most of the guns used in the film were water pistols. However a few were real, borrowed from the town's police force. In a shot near the end of the film just after the Mariachi is pulled out of the yellow Ford van by Moco's henchmen there is a shot of Moco walking towards the camera. Behind him laying asleep on a bench is the cop who was meant to be on-set supervising the use of the weapons for that day.