I am looking to setup a adult pay site with video and image galleries which free plugins do you recommend??
wp-ecommerce might work for you. Don't expect everything to be free though. If you expect people to pay for your content then you may need to use higher quality plugins to prevent theft, hacking and to improve the user experience.
I am thinking about using this to handle the memberships it is free http://wordpress.org/plugins/paid-memberships-pro/ Then I would been something to handle the content all the videos and images