Custom multi drop down list form on Wordpress

General information for the website: A new website which allowing customers to book a service for their car online.
Kind of development: Customization of existing website
Num. of web pages/modules: 1
Description of requirements/features: This is a specific project for the development of a single feature, rather than a whole website.

We'd like a feature to run on the site similar to the one that runs on http://www.service4service.co.uk/

The idea is that the customer selects the Make from one drop down list, then the Model from a second drop down list and then hits a 'price' button. They are then taken to a specific page which shows them the price for servicing their car. There are 6 service price options that we will offer to cover all makes and models.

We can supply a spreadsheet with the makes, model and price page options to help with the coding.
Extra services needed: Customization
Similar urls: http://www.service4service.co.uk/
Extra notes: