Does everyone with a domain name such as www.pstone.com have a server or is there a company that provides these services at a cost? The website is only a example not my site.
Most domains are on shared hosting plans. Meaning that you share one server with several other people. Googling for hosting would give you some results.
There are many hosts/hosting threads here on DP as well. For instance, I do hosting on the side. There is even a hosting forum here on DP...