I am just starting a theme site can i download free themes from other theme sites and put them onto my site i know i cant do this with paid themes but are all free themes free for disruption?
You need to read the terms of those other sites. My thought is no. You would need to have the owner or creator of the themes submit them directly to you.
Most of the free themes released under http://creativecommons.org/licenses/by-nc-nd/3.0/ with term and condition - the footer credits must remained. Why not send them an email before list the themes up on your site? Good luck.