If you are going to create a business website or a blog, You need to register a domain and hosting.
There are many sites where you can buy cheap domains, domain names registration is varies from $1 to $10 depend on their promotions on domain registration.

There are number of web hosting sites, But I will recomment you top five web hosting here.

1. Blue Host
2. Hostgator
3. iPage
4. godaddy
5. wordpress

If you are going to build word press website, then Blue host or wordpress host is best option.