adding a page to existing website

I need 1 new page added to an existing website. [login to view URL] The page will display a new product and service that will have to function in the same way as the other service pages. It will need to function for selection in shopping cart as well as in my admin site to be able to change pricing only and the admin can be shown to whom ever win s bid. The page content will be a water product service. it will have 3 - 4 add to shopping cart functions also will need to add a discount function in my shopping cart. And what it takes to make the website in to mobile app function