Nothing stops them, but that’d be fine. If they buy the hardware they should be able to do what they want with it.

There would have to be some very clear benefits for that price.

Agreed, it would need to be very clear, and additionally we’d need to plan that a certain percentage of customers would grow out of a basic support offering, either by becoming experts or by growing their install size and complexity.

$20 per month would be enough to discourage me. It’s another relatively costly computer-related subscription and I already feel like I’m losing a battle to keep those minimal.

Understandable. Is there a price you think would be reasonable? What would you want for that price?

How will you provide long term maintenance of their server for a one time payment of 150$?

My current thinking is the margin on the hardware would be intentionally low, essentially the cost of the hardware %+10 for configuring it a bit, installing NixOS, etc.

The business would survive on support and hosted services. Something like $20/month which gets you access to support to answer questions, help configure applications, troubleshoot issues, etc. Possibly rolling upgrades of your installed software on your behalf. Alerts on urgent security vulnerabilities. Could also handle tricky things like custom DNS (email servers, certificates) and off-site backups. I’m not totally sure what all would be included, but the goal is to make money while providing value, not build a garden or rent-seek.