Abstract: A portable, handheld computer apparatus is used by a contractor's representative to determine the price of construction services at a job site in real time for presentation to a customer. Stored in a memory of the apparatus is data providing costs of a plurality of different construction materials used in building a structure at the customer's job site including at least some visual images of different construction materials to be displayed on the apparatus' display screen. This enables a customer to see the image and make a selection of materials while at the job site and after viewing the images. The apparatus has a program that based at least in part upon the specific materials selected by the customer and other information entered by the contractor's representative determines the total costs and a profit. The contractor's representative while at the job site and in real time may present a contract to the customer for the construction services.