Create Service Calculator Using Gravity Forms

I require a calculator to be created using Gravity Forms. The calculator is based on approximate cost of services. 1. The user selects 1 or multiple services - Services listed as images. Example, an image of a Car Tire, or Car Battery. 2. The user selects the service (or services) then describes the approximate amount. This is the calculated to give an answer of an approximate cost for service. If you chat with me I can give you more details and also an example website.