No Budget: Subverted: the budget was quite high. Except... three words: Cardboard MRI machine.
It looks like it has no budget but it actually had a shooting budget in the tens of thousands and a post production budget in the millions (mostly for distribution and the CGI sequences).
The film seems to have an obsession with printer paper. It's even used for props like a prison sign. To establish that a criminal in one scene is in prison, they typed "Cell Block #" and then printed it out and stuck it to a wall.
It doesn't show because most of the budget is post production and distribution with a lot of it being wasted on expensive CGI software that is ineptly used. They could have gotten more for their money hiring a render farm to handle the CGI segments and they had the money for it.