Domain name is the name of the site which leads the users to reach your site I.e., domain name is like house address and this domain name points to the real address IP address. You need to register your domain name related to your business in DNS, and then only you will get owner ship and rights on the domain name.
Generally domain name costs $10-$50 per year and it varies with the extension of the name. You cannot directly do the business if you register the domain name. You have to develop the website and you also need to establish web hosting server to store your data.
Web hosting is portion in the internet server to place all your data related to your website files and database are located and users will be accessed to this data whenever the users visit your site for the information. You can upload the data of your site when ever required.
For the storage and information you need to pay and the charges range from $10 to $50/ month and it depends on the type of server you are using to store the data and how much space and band width you are using.
The site files are files which are visible to the visitors and potential customers to see your products or services. The site files like .jpg, .mp3, .co,.org, .uk, .php files, and html files. The webhost know how to read all the types of files. The web host will read the file and displays the required file. The web host filters the required content from the competitors.
You have the visitors to your site; they will go to your domain name, which translates into IP address and the servers will send the site files to the users typically it is a web page. You cannot have a website without each of these elements.