On a TCP/IP network, each host has a host number that, together with a network identity, forms its own unique IP address. In the Open Systems Interconnection (OSI) model, protocols in the transport layer, also known as Layer 4, are responsible for communication between hosts. Hosts use various protocols to communicate, including transmission control protocol (TCP) and User Datagram Protocol (UDP).
It shouldn't come as any surprise that, like other web host providers, A2 Hosting's unlimited plans aren't actually unlimited. It expect you to use its service like "similarly situated customers." This is like being on a highway. If everyone is going a few miles above the speed limit, you're probably okay, but if you're barreling down the fast lane past everyone else, you're probably going to be asked to slow down.
Contact the owner. Before so much as hinting at a price, simply email to ask whether or not the domain is for sale. If you are known or can clearly be linked to a thriving business, create a generic alternate email address through which to contact them, as your success might be leveraged against you. Be aware, however, that an informal-sounding email address is more likely to be regarded as spam or junk mail.
Migration or transfer services are often free or offered at a reasonable fee. These services help move your existing site to the new hosting provider. They can save a huge amount of hassle. Just remember that the migration process is often automated, and may fit in with the host's processes and needs rather than yours. Not everything may migrate, and you may find the organization of the newly migrated site makes for harder maintenance in the long run.
The server where you bought the domain probably offers hosting services but usually at a cost. If you want to do it for free, have your domain redirected to whatever free web service you decide to use for your website. Remember, free sites are limited in the number of pages and can have a lot of ads. On the other hand, hosting your own website as in Method 2 above, or having your site hosted where you bought and keep the domain, allows you to pretty much create as many pages as you want, without any advertising you don't put up for yourself.
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.