I need a simple multi price subscription builder

General information for the business: We offer healthcare membership packages
Kind of development: New program from scratch
Num. of modules: 1
Description of every module: We need a membership package builder for internal demonstration use only. This should be a table with a list of services such as: GP Consultation, Health Screen etc. The user should be able to add or subtract services in the process of building a membership package. The goal is that we have a tool which produces a monthly subscription fee for the user based on the services they have added to their subscription package. We will obviously supply the services, prices and calculations.
We have a table within excel but we need something we can take to presentations that looks and functions like a customer facing tool.
Description of requirements/functionality: Within the module, the user should be able to add a service by either using plus or minus buttons or by typing the exact number they want. So for example, a user wants to include 4 GP consultations to their membership package, they can either press the plus button or simply type 4. As they add or subtract services, their monthly payment calculation should update. So for example, if they select 4 GP consultations and nothing else, their monthly payment would be £18.33. However if they wanted to add a standard health screen to that package, their monthly payment would rise to £33.33.
There should also be buttons seperate from the module. These buttons would say "Basic Membership" or "Premium Membership" and when pressed would pre-fill the services within that membership. This is essentially allowing the user to select pre-sets rather that building from scratch.
CMS and Admin requirements: None, this should be a simple internal demonstration tool to show how users could build their own membership package and monthly price.
OS requirements: Windows, Mac OS
Extra notes: