Hello,
We have reviewed the brief description that you have provided.
The accompanying bid, along with the time estimation is quite a ballpark one. The description of the project is currently very general. We need a more detailed description to make a proposal.
To estimate the exact price and implementation time we will need a bit more detailed understanding of the project.
Imagine, you have the final product done and completed, in front of you. You could start with either mockups of every screen that you see. Or just describe in a couple of sentences what is there on every screen of your project and how it works from the user point of view.
Feel free to provide an NDA if this is required to disclose further details of the project.
We will implement this project using Symfony framework for PHP for the LAMP architecture (Linux, Apache2, PHP5, MySQL5).
You will have a backend with a CMS admin area, where you can edit content without any technical knowledge.
The mobile-friendliness will be achieven using media-queries (responsive) technology, however, we would advise you to consider a later creation of native standalone apps for iOS and Android platforms. Mobile devices have a principally different user interface (touch), so a native application would really enhance the user experience.
The growth-optimization is considered in every web-project we build. We optimize database queries and always use proven caching mechanisms. Most of the methods are already included in the Symfony developer MVC framework that we will use for this web system.
You will find examples of our projects and their descriptions in our portfolio here at http://www.freelancer.com/u/devexpertsteam.html
Best Regards,
Andrei