Went through the same cycle, of first releasing an open source software that had donation support. Gathered an user base over many years, at max I was receiving maybe 500 - 800 USD in donations over a year, after working on the software like 3 years.
Was really reluctant to make the software a commercial version, because I was limited in my thinking that software should be available for anyone to use. You can't make a living out of that, except in some very rare cases.
Once we launched a commercial version of our software (https://OmniGeometry.com), got a lot of backslash from users complaining about the price not being free anymore, and actually we priced the software lot higher than people usually do, but we are implementing something that fills a very specific niche, where we have almost no competition.
As a result of that, we are now actually making money that can support the continuing development of the software and can support our two man team as creators. To be honest I am surprised that we managed to do that, but are very happy about it of course.
I agree with what is written in the article:
"Don’t let anyone tell you how much you should charge for your work"
Writing software can be very difficult and complex, and usually takes many years to reach anything usable and even then it is a risk if it will become anything that people will use.
Almost certainly you will receive hateful or resentful messages from people if you are charging for your work, as on some levels they would like to use your software, but would like it to be free also, so they just lash out at you for not making it free.
Something just have to get used to when selling software these days it seems. If people had any idea how much skills and dedication it requires to even be able to write usable software, maybe they would agree that paying for example 200 usd for a software package that will give you possibly hundreds of hours of entertainment is a good investment.
Feel free to ignore the choosingbeggars who are after freebies, but pricing is a dark art, and IMO when making the leap to charging money for things you've built, it seems way more common to undercharge, especially for apps like Sizzy made by perfectionists.
Patio11's article on SaaS app pricing: https://training.kalzumeus.com/newsletters/archive/saas_pric...