Drop down menu/interactive calculator for patio estimate for website

The name of the business is Louis Lawn and Landscaping LLC. We are looking to add a feature into our website that would allow customers to pick from a drop down menu, style of stone, that then leads to another drop down menu appearing showing what size of the of the space that then shows the customer a rough estimate cost of their project. Not sure about this next part but if the client is interested in that rough estimate can that information be sent to us as a forum. Our website www.louislawnandscapingllc.com