I'm not sure it works this way, for me, as far as setting a threshold for money being off the table.
I've always been interested in getting paid as much as I can for any writing projects I undertake. But if the pay rate turns out to be nothing (or a token sum), it doesn't discourage me from wanting to write about stuff that I'm interested in. The way that payment rates limit me is that low or non-existing rates stop me from spending as much time writing the stuff that I would write, anyway -- whatever the pay rate for that stuff happens to be.
Ten or fifteen years ago, I could get paid more than a living wage to geek out with computers, explore the nooks and crannies of hardware and software and write about my findings in books, magazine articles, and on websites. So I did that. There was a high market demand and pay rate for magazine and web pieces on more generic aspects of personal computing. But I was just as likely to pitch and take on an assignment for 10 cents a word on something geekier that really intrigued me. I wrote reviews for the New York Review of Science Fiction for only token payment, because I thought it was the place to be -- a focal point of interest in science fiction. The better-paying work covered me to take on the assignments at lower rates.
Now, there's no higher-paying market in computer journalism that's accessible to me. I still write geeky stuff on computer operating systems and reviews of science fiction and graphic novels for token payments -- because a) I'm interested in the exercise of thinking about those subjects and expressing myself and b) I'm under the impression that the publication points are reasonably high-traffic focal points.
I have to earn my living, now, through non-freelance writing work: salaried IT support and document production for a software company, and instruction/course design for a vocational college. (I did those things ten or fifteen years ago, too, but I didn't have to spend most of my work time doing them.) I still get to do a little bit of paid writing in these jobs -- but I'm no longer my own master on choosing content and setting my own production rate.
Edited at 2010-05-31 09:04 pm (UTC)