As I said, it depends on each site so get your finger out of your ass, I build websites and some run on servers which cost less than a coffee a month and some go into the hundreds per month.
A forum can be incredibly server recoursive, I have worked on quite a few over the years, for example, ukbusinessforums.co.uk gets hundreds of thousands of visitors a week, it won't run on a $5 server, there server costs will be eye watering.
I was feeling a bit server recoursive earlier, luckily it passed
