I would like to share the key to my startup business model: no expenses. That is it. Two words. No Expenses.
I know that it is not possible to literally have no expenses. I had to pay a state registration fee for my LLC. But no expenses is my goal. So, I found some accounting software that is free, a discontinued Microsoft product called Microsoft Office Accounting Express. I downloaded it and installed it and it seems to work just fine and meets my needs. For free.