Bad old business* says, “How can I maximise profit? I will use up the resources available to get as much as I can.”
Naive charity says, “This should and must be free… But I don’t have a clear idea of what it costs, or who will pay, or where ‘free’ should end, and how I will stop it from being used up by everyone.”
The better path, either for- or non-profit, is to ask: “What can I provide to be of service, and what’s the right price to make it work?”
You’re looking for the price that will make the thing sustainable by helping people to recognise its value and by providing sustenance for those who make it, but that remains generous: the benefits users receive should be worth more than the price they pay.
This is the Goldilocks spot, where the price is “juuust right.” It’s the price that will enable you to do more useful things, better and for longer, than you would be able to do at either of the extremes.**
*Bad Old Business may be a charicature, but he’s too often been true.
**Disclaimer: stealing from bears is unsustainable in several directions.