I'd put up a specific landing page, where you offer to demo, and on-board potential new clients.
I'm not sure what your stick rate, or your ascension rates are, but if you're at $50 a month, and you're keeping a client for a year, you can easily spend $500 to acquire a customer and still be profitable.
That's how you have to look at this. The cost is going to be high up front, but maybe you can acquire customers that work for you over the long term.
You're not going to pay $10 to acquire a $25 a month client, that's just not realistic... especially with such a specialized service.
I mean, it feels to me like this whole post just reinforces the idea that ideas are worthless.
Without the development, meetings, patents, copyrights, lawyers, etc, nothing happens here. The only reason you were successful in the end is because you didn't have an idea, you had an idea, that turned into research, that turned into a prototype, that turned into a product, that was then able to be protected through patents and copyrights.
The idea itself was worthless, the execution on the idea, and the protection of the work are what mattered. In other words, the execution all us "ideas are worthless" guys always talk about was really what saved you - it wasn't the idea - it WAS the execution.