Honestly, ever dollar helps, and it doubles as an easy gauge as to whether people really want a project, or if they would just ‘like’ to see it.
That really goes for anyone’s projects, a buck or two or five is always appreciated, as much for the sentiment as for the offset of costs. A lot of people who work on these various projects put hundreds or even thousands of hours of their free time into making them happen, call in favours, take risks and spend more of their own money than is even vaguely sensible.
When you see people chip in anything to help, it really, well, helps. There have been many times sitting alone at 3am that you feel like giving up, looking at an A/B roll of frame #114003 for glitches you may have missed, or logging a missing frame, and then you get a ping with a message that someone in another timezone on the other side of the planet has donated five bucks, and an accompanying message that the movie held a special place in their life for their own special reasons, and you get a second wind - it keeps you going, and reminds you of your own passion for this stuff, and you keep plugging away it.