I have to get a value in $.

I have 2 radio buttons:
Residential Customers
Business Customers

I have 2 List boxes:
Premium Channels
Connections

I also have a total Text Box and a calculate button



My goal is to get a cost given the information from the user. the list boxes will have preassigned numbers in them


Variables:
The residential Customers have to pay a $4.50 Processing fee, a Basic service fee of $30 and 5$ for ever Premium Chanel they buy.

The Business Customers have to pay a processing fee of $16.50, a basic service fee of $80 for the first 10 connections (4$ for any connection after that) and 50$ per Premium Chanel (no limit)


Can Anyone HELP?! I am totally stuck!!

The project calls for a Sub and function procedure.