Develop a mockup prototype ONLY for a cars buy and sell website

You need to collect requirements, list down key functionality, and design/develop a working mockup screens walk through website for both pc and mobile versions. This means that the website will not be true functional but will contain the design look and feel, links, etc as a mockup which I can then use as specifications to tender for the real website Milestones value and schedule: M1 = 10$ = collect requirements and draw a conceptual design using powerpoint or any other prototyping technique M2 = 20$ = develop the draft mockup website with all pages and links containing the key functionality mockups to show roughly how the website will look like M3 = 20$ = develop the mobile version mockup for mobile orientation M4 = 50$ = refine and finalize both versions of the mockups containing all links to needed functions (no actual functionality) and deliver the source code initial listing of needed requirements: - profiles and sign in - post ads for free + featured ads (paid) that always come on top - post ads with cars specs - search abilities - private messages and chat ability with guests and users - likes and comments - stars rating 1 to 5 or 1 to 7 - upload pics - upload and view videos and 360 degree + VR - integrate with google maps to plot location - integrate with facebook and google+ for sign in options - integrate with facebook and google+ for posting ads on the social networks - upload setup data of all car types and models