Adding another story:
I was ghostwriting a book for a best-selling author [how to land that gig explained below]. Now, I'm not FI, but I have passive income that is very helpful, so I can afford to negotiate a deal like this: I will work as much as it takes to create a high-quality product to your liking for royalties with no limit.
"Do you need an advance?" he asked. "Monthly pay?"
"Nope. Just the chance to show you what I've got."
For the next 16 months we ended up writing what I consider to be 3 versions of the book, which could have been 3 overlapping products (not uncommon in the self-help business). At the end of it he said he wasn't happy, and asked to settle up.
I said, "You owe me nothing."
"No," he said, "you've put your heart and soul into this. I have to pay you something. How about $10,000, or if you can wait, $25,000 on first royalties."
"But there won't be any royalties," because I failed.
At this there was a silence, and he filled it by saying "But who will own the intellectual property?"
"There won't be any. But if you find some content you can use, I'll get a percentage of the original royalty deal."
"Look," he said, "I want to reward your efforts, so think it over and let me know."
My estimate was that I would make $300,000 off the book, so I emailed him a long analysis that settled on
(a) $50k today, or
(b) $25k today with another $50k on royalties over the first 100,000 copies sold.
We had some back and forth. He concluded by saying his offer of $10k was generous, and that I was greedy.
I said, "Let's go back to our original deal, dated xx/xx/xxxx," where I got paid only if something I created was used in the final product.
Maybe I was just stubborn to let go of the bird in the hand, but the truth is that I didn't need $10k. I take that home about every 4 weeks. What I wanted was a best-seller and $300k, preferably 5x over. He has not released a book since before we worked together.
[How to land that gig]
I shot gunned it - contacting publishers, agents, authors, athletes, pretty much anyone - trying to sell something else I'd written. This guy didn't get back to me, so I followed up twice and we had an hour-long conversation that concluded with him asking if I'd consider writing an updated version of a previous best-seller about how the web is going to make billions!. We ended up creating nothing, but I'm still trying.