To setup a website you need to buy Internet domain name. The domain name can be any name you like that is not already taken. There are several extensions that you can choose from, including, .com, .net, .org, .biz, .ws, and .us (if you live in the US) are some of the more popular ones. If you have plans to monetize the site you should consider using a popular keyword that will help draw some organic traffic. This will bring customers to your site without having to do a lot of expensive advertising. You can also do some SEO on-page and off-page to help draw even more organic traffic. Domain names will cost you less than $20 per year depending on the extension you use and you can pay in advance several years usually for a discount. You will also need Internet domain hosting (web hosting) which will cost you less than $10 per month and you can get some good discounts by paying a year or more in advance.
Purchasing Domain Names and Domain Hosting
You can find low cost domains from several domain name providers. However, GoDaddy is very competitive and provides a good domain name service. Hosting is also very competitive, but Host Gator is one of the best and provide web hosting free domain service. They are very reliable and host on newer equipment with good bandwidth. You can even reach them behind firewalls.
I have tried some of the newer domain extensions, such as, .ws and .biz with mixed results. They seem a little more challenging to rank than the traditional .com and .net.