Startups expecting free work?

I don’t understand where people get the audacity to expect free work on their terms. A friend of a friend asked me to meet about “hiring” me part-time on their startup. I figured I could probably work on it a few hours a week, so I messaged them back and had a meeting. They said they expected me to volunteer and I wouldn’t get any money or stock. I laughed. Then they said that I’d need to put in 10-20 hours a week on a schedule doing software development work and I’d *possibly* get a chance to get paid in the future. They told me that they know I do great work and I would be a valuable addition. Apparently not valuable enough to pay haha. Obviously, I’m not doing that. I just don’t understand where people get the expectation of free work from. It’s crazy to me! If I started my own startup, I wouldn’t expect to hire anyone on unless I was able to pay them to give them a part of my company. Is this a normal thing in the startup world? Edit to add: They also went back to my friend and said that I was “unhelpful” and “not dedicated to my work as a SWE” because I wouldn’t volunteer my time. It’s laughable haha.