I’ve done a few things for free, but at my initiative - either because the other person was giving out something for free that I used and wanted to help improve or because I liked their work and wanted to buy it but couldn’t figure out how from their website. It’s one thing if you volunteer to support something you believe in.
But a businessperson (or wannabe) asking for free work would be quite a different matter. When I was contracting, I had no problem shutting off even ‘paying’ customers who dragged out the payment way beyond when it was due (“Because paperwork, but can’t you just go ahead and do this other thing?” “You do the paperwork for what you owe me and when I get the check then we’ll talk about new things.”). After awhile, I just refused to work for anyone who wouldn’t pay a good chunk down in advance.
One potential customer refused to pay anything in advance, and right at that time I quit contracting and went to a full-time job. About a year later when that contract would have been up, the potential customer contracted me again and said the contractor that they got instead of me didn’t work out and would I reconsider - they needed someone to fix what that contractor had done. I just said no thanks.
Customers/clients who can’t or won’t pay are the worst to deal with. The ones who are already successful and pay well with no complaints and no questions asked not only pay better but are more importantly far easier to deal with. They’re also the ones who, when you have to tell them that you’re raising your rate, just say “ok no problem, and by the way we have more work for you if you can do it”