Yes, most Subrion plugins are free. You can find a plenty of free plugins in your subrion.com -> downloads -> plugins area OR here: http://www.subrion.org/plugins  . Every plugin that was created by 'Intelliants LLC' is free (except Premium Radius Search plugin).

You can also find many other different plugins which were made by 3rd party authors. These plugins can be paid or free depending on the wishes of plugin creator.

For example, plugin which was made by 'Intelliants LLC' - http://www.subrion.org/plugin/personal_blog.html - is free and author is 'Intelliants LLC'

and plugin which was made by 'wazza' - http://www.subrion.org/plugin/pm_picasa_albums.html - is paid and author is 'wazza'

Thanks for your interest in our software products!