Payment gateways in Membership Pro plugin

If I create a monthly subscription for users, will Membership Pro auto-charge money from them? or it will only send them emails asking to pay?
Also can you suggest anything that will allow to give users a free month subscription for FB likes?
Also have you got any plugins for social integrations, besides FB? I've tried g+ but for some reason it didn't worked.
Also have you got any solution for custom users avatars on non-multisite websites?