There are 1700 million websites, of which around 200 million are active. Even of the active websites the vast majority are accessed less than once an hour, more like once a day. Most small businesses host their website on some paid location. In general this is a good idea because a small business would host at most one website. A host provider such as Godaddy will also provide access to tools like WordPress, MySQL, Joomla and Drupal.
The cost is reasonable… about AU$14 a month, excluding the initial overheads of domain name, SSL certificate and so on which will be incurred no what where the website is hosted.
However there are good reasons to run the website in-house. The main business case would be that it is easier to integrate the business database with the website. For example if the business sells widgets then customers can know in ‘real time’ whether the specific widget they are looking for is in stock or when they can expect the widget to be available.
If the website is hosted externally, it is possible to have the remote web server access the in-house server for the details, except, for all that trouble it is easier to host the website in-house.