Several requirement you need to consider before build a web site as follows:
1. website domain (either Free or paid one)
2. hosting (free/paid)
3. website source (basic html/CMS/website builder)
Ok lets go for detail. For the first one is your website domain. If you a beginner, just want to start create a website, just create a free domain from developer-hosted such as freeweb.com, blogspot.com, wordpress.com. If you want a professional website which want to have yourownname.com or .net, .org and so on, then you need to purchase a website domain from reseller (e.g: domainsite.com). If you want to start a biz, it is better for you to purchase a domain.
What is hosting? Hosting is your online storage to locate all of your website files, images and so on in online server so that can be access by the visitor. Hosting also have two types, free and paid hosting. Usually if you choose free domain which is developer-hosted it is already come with the free hosting server and no need to use any paid hosting. But if you choose to have paid domain then you need to use paid hosting. Although there is also some free hosting for paid domain.
The last part is your website files. Are you want to create a basic HTML (static) website or use a system such as Content Management System (CMS) or website builder to create your dynamic website which are easy to edit and updates. If you use blogspot or website builder system, it is also a system that you can use to have dynamic website that are easyli to edit the contents and updates.