Have you thought about a model similar to WordPress where you offer the software for free for self hosted clients (arantor.org), but also a paid service for clients who don't worry to worry about hosting (arantor.com)?I suppose it wasn’t *entirely* clear that I was only planning on charging the admin for hosting the site, as opposed to members for access. This runs back to a conversation months ago about building a new forum software, where I was going to go open source and give it away until, well, I was convinced not to.
Though I also would have thought that “trying not to make a business out of it” and “just cover the costs” for what is essentially a hobby project makes it less transactional by nature and returns it to the spirit of old where its not about making a profit, and any money changing hands is necessity.
That stays true to your mission of building the software for the sake of the software, while also commercializing a portion where clients want to pay for add-on value.