Instant Estimate Script

I need a script which will allow visitors to my website to enter different values in a form to receive an instant estimate of their considered project; This needs to contain the following features: 1) Estimate can be seen as the visitor enters different values, in real-time, on the same page (without having to click to another page to see results). 2) Be easy for me to configure when I want to add discounts, add/subtract services, add different variables to existing services, or change prices, etc; (I am not a programmer so this has to be made to be easily understandable). 3) Be customizable (using css?) to match my website. 3) Be configured where both the visitor and I will receive a copy of the estimate via email. I will send the link to my rates & estimate request pages as reference upon request.