[mothered]

Hosting Is where the majority of the cost Is. And then there's the cost of protection against DDoS, code Injection attacks etc by using a WAF such as CF.

The domain name Is hardly worth mentioning. For a .com domain Inclusive of privacy protection, you're looking at around 25$ annually.

I haven't checked but, Xenforo is $50+. Could be the equivalent.

In terms of forum software, this board uses MyBB which Is free and open source.

phpBB Is also the same, but not as flexible as MyBB. What the latter can do with plugins, I've had to actually code for phpBB.