Businesses strive to have customers, ergo SolTech is not a business; or at least has a business model that differs from the usual making-money, lots-of-money, and more-money (as extracted from 'customers' by whatever means) business plan. The founder is a semi-retired software developer/ER RN. As a nurse he had patients, aka clients, but no customers. At some point someone would come around to collect financial information for the hospital who had the hope of eventually getting paid, but the nurses and doctors could care less as long as the bean counters stayed out of their way. So SolTech has no customers, only clients.
There are, of course, expenses, not to mention all the time and effort, and covering expenses helps to keep up the good work. But as for profits, if the beloved founder of SolTech can take his beloved wife out to dinner once a month, he feels well paid. The real pay-offs are all the fringe benefits: the joy of product development and testing, helping others, the spreading of memes.
All SolTech products are considered open-source. Copy and Paste if at all possible. If the ideas offered are enough, then have fun. If you want (preferably need) a SolTech product but are not DIY enough to roll your own, then SolTech can help. If you just need the tools, move to Tucson, AZ for a time, pitch a tent, come by the SolTech shop whenever possible and build what thou wilt. If you have extra time to volunteer, can pay for electric used, for a bit for wear and tear, then we'll work something out.
Since riches beyond the dreams of mindless avarice have yet to task the founder with the need to find ways to give it away, those who say they need a Greenspeed Magnum trike cannot be given one. SolTech could sell them one, a client could hunt Craigslist for a used one—no matter; and if SolTech helps procure one, then some money exchanges hands. So, yes, SolTech is a business, but seriously, in the scheme of life, the universe and everything, money is not the axis about which life should spin.
If you happen to have some money, great. Do some good with it before you die.