Social network + content sharing website(Working Prototype)

I need help from an experienced developer to build a simple social networking + content sharing website. This site should provide following functionality 1) Basic security settings(who is allowed to see contents) + sign in(sign up) process 2) News feed page with multiple tabs 3) Content sharing like texts(comments), pictures, videos, web link etc 4) Invite friends I will prefer to use open source technologies especially NoSQL databases like Cassandra but in general I am flexible. I will prefer a simple and elegant template like FaceBook but I am open to developer innovation. Please note my budget is limited, so I am looking for a working prototype with a solid architecture which can handle high volume of users and I can fine tune website by myself. Thanks and looking forward to hear from you.