andreherberth Thanks for your thoughts! I do think that it is possible for projects to be sustainable without monetary basis (eg the non-commercial open source Flarum project), but they need a strong vision and values to drive its contributors. Lacking that, a viable business model may be a good substitute.
At the moment, FreeFlarum runs at a (small) loss, but I am ok with that, because I value other things. Should I, for whatever reason, stop supporting FreeFlarum and no other volunteers would step up, a number of commercial parties are likely keen to take the stack and install base and turn it into a paid service. There have been a number of commercial initiatives already.
Despite the title of this thread, I don't see FreeFlarum as a free VPS replacement but as a software-as-a-service (SaaS). The actual server capacity is practically free. 99.9% of costs are in software maintenance (handling upgrades, debugging mail delivery issues, incompatible libraries, optimizing mysql buffer sizes). When you run your own VPS, you have to do all these things by yourself or hire an expert.
If I may ask, what are your reasons for not having a Paypal account? Apart from their ridiculous transaction fees 🙂