I've been using open alternatives for quite a while now. I think one of the most useful things I found on the website was a self-hostable customer relationship management software. I've been hosting it on Pikapods, which is a really nice way to host open source software easily. I definitely recommend it to anyone that wants to try this out! Looking at the price difference in this specific case for the cloud solution from Twenty, I would be paying $12 a month, but self-hostable solo, it's free. On Pikapods, I'm paying around $6 a month. You could also host it yourself with Docker, but that would need a machine that you can run it one. I think that's definitely something to consider if you're running multiple self-hosted instances, because then it starts making sense financially.