Apache HTTPD is not a really resource-hungry program, although it will happily spawn multiple threads for performance. I have one server whose
thread memory lists at a "mere" 240 MB virtual.
Total resource requirements depend very much on what modules are installed and in-use and what resources the webapps and their frameworks (such as PHP and django/python) consume.
However, a Raspberry Pi is quite sufficient for many things.
If you have a 2GB RAM/2HGz CPU/5GB disk machine, you're pretty much home free. That will host Apache and quite a bit more.
The secret of how to be miserable is to constantly expect things are going to happen the way that they are "supposed" to happen.
You can have faith, which carries the understanding that you may be disappointed. Then there's being a willfully-blind idiot, which virtually guarantees it.
