I am looking for a software license for a tool based on the wealth of the party using that tool.
For example:
- If you are making no money using that tool, then it is free (as in beer, this license is not about open source software).
- If you are making only enough money to support yourself using that tool, then it is free.
- If you are making more than enough money to support yourself using that tool, then you need to pay a licence fee.
The big problem that I see ( unless your software somehow reports revenue it generates to you ) is that you have created an incentive to cheat. Either by misreporting or not reporting at all, income that is generated by the tool.
Leaving aside revenue models that involve planning on profitable litigation (never a good idea).
What you need to do is figure out what features of your tool are important to people who would be making money off your tool and split your product into Free, Functional and Full product tiers. The free product tier may have all the functionality of the full version, but have severe drawbacks in its usage model; for instance if you are building a financial strategy analysis tool, the free version might post your analysis publicly, whereas the Full version would keep it local and the Functional version would send it to you, but not the rest of the world.
IOW the free version is a taster, not something you'd use if your were serious, mickey mouse, etc.
The Functional version is effective for normal use but has limits that make it desirable to upgrade.
The Full version does what it does without limitations, without silly games, and with full support and plenty of extra/optional features.
Does that sound like work? Welcome to the world of business.