No, as long as the blog is hosted here, (domain name or not) you still have the restrictions here.
To use plugins you would have to get your domain name, hire a web host such as godaddy, bluehost, etc., install and configure the software from wordpress.ORG, and if need be, export your stuff from wordpress.COM and import it into the new blog.
http://en.support.wordpress.com/moving-a-blog/#moving-to-wordpress-org
You should figure on an average monthly cost (all things considered) of about $10 to $25 depending on bandwidth and storage requirements.
You will be responsible for all installations, all upgrades, all backups and all troubleshooting. If something goes wrong, you have to figure out what that is and fix it.
WordPress.COM now offers a guided transfer for $119 where they set everything up for you and transfer all your content over to the new self-hosted blog.
http://en.support.wordpress.com/guided-transfer/