One of the challenges in giving a tool away for free is the idea that “we might-should-ought-to-be-able” to make money off this tool. This idea is simple: the tool, in our view, is fantastic. We ought to be able to publish this [film, book, tract, magazine, fill in the blank] and sell millions of copies and solve all of our fundraising issues. The problem is: in all reality we rarely sell even thousands of copies.
There are nearly always reasons why runaway best sellers are, in fact, runaway best sellers. There are a few exceptions to these rules, but most of the time there is a lot of groundwork laid before the book or tool or film goes on the market, to maximize the possibility of viral, word-of-mouth references that will lead to huge sales.
As Cory Doctorow quotes Tim O’Reilly: “The big problem isn’t piracy, it’s obscurity.” Most people simply don’t know about your terrific tool. Doctorow’s approach is to allow anyone to download copies of his work for free, while at the same time offering it for sale. His reasoning: downloaded copies serve as a form of advertising. Some smaller percentage of those who download will purchase, and he’s hoping his numbers are high enough that he can make a living at it. So far he has succeeded. Others have not.
In terms of your vision, here’s the question before you: is the book/film/whatever that you have developed instrumental or incidental to fulfilling your promise?
If the tool is the key to do what needs to be done, think long and hard about whether you want to require people to pay for it. Requiring payment automatically limits the pool of actors to those who can afford it. If, on the other hand, the tool is incidental to the promise—for example, a collection of biographies of people who did what you’re suggesting—then it might very well be worth it to sell the book as a fundraising tool.