These services offer off the shelf set up and template's without the need to know what HTML, CSS or Javscript is and cost different prices depending on your needs.
A domain is the address of your website such bbc.co.uk or google.com. These have to be bought separately and although most of the above will allow you to not use a custom domain, they don't tend to be as neat, Usually in formats such as adamprocter.squarespace.com. Some of the above services offer domains as well however a very simple and straight forward domain purchasing service is hover.com.
Sites that allow for much more customization and own hosting.