If you register a domain with Bluehost when signing up for a hosting account, there is a domain fee that is non-refundable. This not only covers our costs, but ensures that you won't lose your domain name. Regardless of the status of your hosting service, you'll be free to manage it, transfer it after any required lock periods, or simply point it elsewhere at your convenience. You retain ownership of your domain until the end of its registration period unless you elect to extend it.
A few companies have offered low-cost, below-cost or even free domain registration with a variety of models adopted to recoup the costs to the provider. These usually require that domains be hosted on their website within a framework or portal that includes advertising wrapped around the domain holder's content, revenue from which allows the provider to recoup the costs. Domain registrations were free of charge when the DNS was new. A domain holder may provide infinite number of subdomains in their domain. For example, the owner of example.org could provide subdomains such as foo.example.org and foo.bar.example.org to interested parties.
By definition, a domain name is simply a human readable form of an IP address. In function it is the destination that you type into a web browser in order to visit a website, such a www.google.com. Metaphorically, it is very similar to how you would scroll to a contact in your cell phone rather than manually dialing the person by entering their full phone number; the phone number would be an IP address and the saved contact would be a domain name. Always buy a domain with a reputable domain registrar.

In terms of what many vendors call unlimited service, Web Hosting Pad's terms of service indicate that their definition of unlimited is what they call "incremental." Basically, as you need more capability, they want to discuss that with you, both to help you get the most out of their services, and to make sure you're using their systems without abusing them.

Moving to another website consists of transferring the website’s files and databases, configuring your site with the new host, and directing your domain’s DNS to the new host. Once you pick a new site host, they can usually help you out with this process. The cost will depend on the host you’re switching to, but it will probably be anywhere from $150-$400.