There are Two things you need to start a WordPress blog:
1) A Domain name (this will be the name of your website or blog i.e http://hostonnet.com).
A web host, or web hosting service provides the technologies and services needed for the website or webpage to be viewed in the Internet. Websites are hosted/stored, on special computers called servers.
You can register domain name and hosting service from HostOnNet.com
Once you got domain name and hosting, you just install WordPress for free and start blogging!