Domain names depend on the type of TLD (top level domain, such as .com or .co.uk) and the period of registration. There are also various registrars you can buy the name off at a fairly low price. Web servers are dedicated servers with certain extra technologies built in such as Apache, PHP and SQL. One example is Ubuntu server which is command-line only and can be configured to run as a web server, Linux servers support mySQL as opposed to msSQL. Windows Server has a GUI and supports msSQL as opposed to mySQL. Oh, SQL is a kind of database FYI.