Build a Website

We have a need to build some UI screens for our web application. We don't expect no more than 20 screens. The screens would be mostly performing Listings and Cred Operations. We have the back end app built already. At the high level, Some of the UI screens would be making webservice call to the backend app which returns the data in a JSON. The UI screen will need to display the JSON data in a well formatted LIST. There will be some screens that would do a POST of the FORM Data "onSubmit". And there would be some doing Cred Operations. We have the complete requirement document listing what each screen will be doing. Since the screens have some proprietary data, we would like to have an NDA signed before we can share it. We would like to receive a ball park quote from you. Based on your credibility and the quote, we will move forward. Interested folks, please respond.