I made Nodewood (https://nodewood.com/), a SaaS starter kit/boilerplate. An unlimited-app license is around $500, so a single sale a month puts me into this territory.

It could probably be higher, if I were any better and/or more persistent about marketing, but right now I'm focusing on the last two releases I have scheduled on the roadmap before releasing "1.0" (easy scripting and an easy deploy system), then I'll switch much harder into marketing for it.