I'm the first guy who wants to save money on a shoot. What you save here, can be applied there. The constraints of a tiny budget force you to be creative and come up with unique and inexpensive solutions. This doesn't have to cut into quality, but can actually make a production better than the one that wastes resources and encourages laziness. When you have to become more organized due to lack of funds, you will become a better filmmaker. Or you'll just quit.
Even in the so-called "no budget" movie there is one area you had better address with some cash or you may find yourself alone on the set one day. That key category is food. You have to feed your people. They have to eat. Film shoots are notoriously long, and humans will run out of energy (and get cranky) without some kind of fuel to keep them going. Do not cut this corner, or no one will want to "work for free" again.
Make sure you ask the cast and crew what they like. A happy cast and crew is a better cast and crew, and you will be rewarded for the attention you give to your people. Some may even have special needs (like vegetarians) and may not be able to eat the bowl of pork rinds you feel is adequate.
I realize that most of us can't afford catering. Shop the discount stores, or really plan ahead and (gasp!) cook the stuff. If you aren't the cooking type, ask mom or your wife. They fully support your movie making habit, right? I prefer a somewhat healthy menu over candy and grease, but something to eat is better than nothing.
I had to learn this lesson the hard way (of course). On one of my first short films shot in my apartment, I thought nothing about food. I'm usually high on adrenaline and eat very little since I'm always busy. Since no one else shared in this particular food group, people started raiding my pantry for snacks. They found what they wanted, but when it was all over, I was hungry and the cupboard was bare. Never again, I thought.
Even if you have no money to pay your people, you had better find some way to feed them. Otherwise, you will not only be known as the "low-to-no budget" director, but also the "cheap and torturous" one.