If you wish to have complete control over a blog, the ability to upload themes and plugins, and to edit themes and templates then your option is to hire a web host and get a free software install from WordPress.ORG and self host it. http://en.support.wordpress.com/com-vs-org/
Please read what I posted above. There is no FTP access to free hosted WordPress.com blogs. There are no plugin tabs on your Admin page because we cannot install plugins into free hosted WordPress.com blogs.