With a shared hosting plan, you are renting space on a server that you share with other website owners. This also means you're sharing resources like bandwidth, memory, and processing power. This can be a problem, because a web host company typically supports hundreds, even thousands, of websites on a single server. Most of these websites will get very little traffic, allowing those who do see higher levels of traffic to use the resources they need. Nevertheless, there are no guarantees that you will get the resources necessary to support your website.
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.