Shared Hosting: This is usually the cheapest form of website hosting because it’s the most economical when it comes to the use of hardware. Shared hosting means that multiple different websites are all hosted on the same server, with each user being allocated a certain amount of storage space and a certain amount of resources. This is often the best option for hobbyists and bloggers.
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.