The software powering edgeryders is called “discourse”, and is Open Source Software. However, discourse hosting is (was?) relatively expensive, and it will not install on the typical 5€/month webspace (because it has some technical requirements that are typically not met by “cheap” webspace).
But my last research regarding hosting costs for discourse for NGOs dates back a few years, maybe the landscape changed. The organisation that is the main developer of discourse offers 100$/month packages, but I am sure you can find cheaper (but if money is not an issue it might be a good idea to support the core developers more or less directly). edgeryders itself offers hosting (sure enough somebody will answer here). I’d be happy if you share insights here if you you find an overview of hosting costs or a decent hosting offer for NGOs.