"...There is no "below cost" distribution in Free Software..."
Actually that leaves the door open to a *fascinating* level "below free" - *pay* people to use your software!
After all, since Lock-In is worth trillions over decades, who cares about a measly 1-time incentive fee!?
I realize you were being facetious, but it's not all that far from reality.
Developers may not typically pay users, but they certainly pay to attract users. Domain name registration isn't free and neither is hosting - usually anyway. There's certainly a payment in time and effort to setup even a modest website to say nothing of a nice one like Donation Coder. That's not including the personal cost of support or adding features just because users ask for them.
That's not to say they don't receive non-monetary payment in return. I tend to see developers in the same light as other creative people. I'm a writer and (formerly professional) musician. I need money to pay my bills but it can't compare to the emotional charge I get from other people appreciating what I'm doing. It also makes me better at my craft.
I go out of my way to tell developers when their software has that same kind of effect on me, and when I can even make a donation - sometimes for premium features I don't care about. It's not as much about financial support as the message. Your creation is so valuable to me I'm giving out of my way to give you some money.
Of course commercial developers pay companies to use their software for various reasons. I once worked for a small company that sold software to trucking companies. When we were launching a completely new product to replace the old one we found a company with an IT guy on staff who had the appropriate skills and gave them a free license along with free support for an indefinite period. In exchange we got their help field testing it and fine tuning features and ultimately had a free showcase to help attract future customers.
I guess my point is payment takes lots of forms and so does value. I'm sort of lucky to be able to pay for software by giving it some promotion, and sometimes providing much needed tutorials or documentation. Most developers aren't very good at that bit and that's fine. If you can make great software I can show people why it's so great. My monetary compensation is nothing to write home about but getting a gifted developer some much deserved attention, and maybe even putting a little money in his pocket, is something I value.