You need to get hosting, a domain name and a way to build that website (if you don't know HTML and CSS). There are some hosts that offer all of this.
I recommend one of these: http://www.tophostingpicks.com
iPage has the best offer right now.
Their plan includes:
Unlimited disk space
Free domain name
(or even cheaper - $3.50/month for longer term plans)
They have one of the most popular hosting platforms, which currently hosts over a million websites. They're also one of the oldest hosting companies, founded in 1998.
They include a free point & click online site builder so you can create a website without any programming (easily, just by drag and drop) or you could install Wordpress (they include easy, one click install from their control panel), choose a theme that you like, and start adding content.
They also have a great custom control panel with OneClick installs of all the popular software like Wordpress, Joomla, Forums, Chat, Galleries, Online stores and a lot more.