Congratulations! I admire your tenacity and commitment. However, > We have not spent much on paid user acquisition Why not spend on paid acquisition? A bit of marketing and sales focus would have gotten you to $8k in 2 years, not 10. I see so many great products on HN that take years to takeoff simply because the founders refuse to market it. Good products deserve to be more widely known so more people can use them.…
> We have not spent much on paid user acquisition, we experimented with it a bit a few years ago without positive results.
It might take $1000 in failed ads before you "get" your audience, but you might quit after spending $100. But the $900 in supposedly "wasted" ad spend will help you understand enough that you can make 10x higher revenue.
If you approach software development as an iterative activity, you should approach marketing the same way too. Expecting great results at first try is akin to expecting completely bug free software at first go without any tests.