I don't even think I was charging very much. I was still pretty junior in my career, so I think I was charging something like $40/hour, which was double my nominal wage at my previous W2 software job (doubled to cover stuff like health insurance and overhead and the like).
$40/hour is an extremely low rate for a software engineer, even at the time. I'm not sure what the guy was expecting, and I'm quite confident that he would have tried to weasel out of paying the second I delivered a product by claiming it didn't match his spec. Honestly I don't really think I'm ever going to contracts for small clients again regardless; a lot of them can get away with a SquareSpace site, and the ones that can't should probably spend their money buying a few courses on using Claude Code or ChatGPT.
There's also the fun scam of wannabe Steve Jobs characters. I had a person try to recruit me for a job where I worked for 2% equity in their business, where I was expected to write the entire codebase myself. Of course the remaining 98% went to them, and as far as I can tell they felt that their "idea" was just that valuable and didn't plan on contributing anything else. Fortunately, I didn't really fall for that one.