Form builder for a landing page

I need a form that can be accessed from a landing page to allow potential clients to complete their information.
I need them to be able to tell me how many dwellings form their project and then an automatic quote to be created depending on their answer. I also want them to be able to add other services, if they require them, and then add them to the overall quote. when they submit the answers they need to be able to keep a copy and a copy sent to me.