Hello, My company has a website management solution that, in the core system, has page level security, page tracking, page creation, content creation, automated navigation system and more.
It is also modular. To complete your project I would have to design the modules for your site. To get you up and running I include script configuration and testing, database configuration.
If I have the code rights to the modules developed, I can lower the price to 2000.
My system is based on MySQL and PHP, so your secondary cost are low I would suggest an SSL which could cost you a bit more, unless you use openSSL on your sever.