Please update your knowledge. Wordpress and blogger are free blogging platform, free domain is something different. Free domain is a domain that you can register without paying a dime, one of the free domain extension I know is called dot tk.If you want to get free domain for your blog you can start by using WordPress.com or Blogger.com to create your first blog. This service is used by those who don't want to pay for both domain and hosting plan. However, it comes with limited plan as their are low stuff you can do with them.