pretty cheap.
Register a domain name. (about 10$)
go here and find a sexy template:
http://www.oswd.org/ (about .000)
then go to host gator (or any other cheap web host) and sign up for cheapest plan. (about 8/month $)
Getting things up and running may be a bit harder, either find someone who knows how to do it, or do it yourself (via researching) youll need to know how to use an FTP, and know what you can do with Hostgator's Control Panel.
Or, just start a blog. It is free and a lot easier.
Blogger and Wordpress are popular.