ahh, i see.
incremental prices are tricky this way, because you want to pass 2 pieces of information, price and description.
The only way to accomplish this is to use a database.
pricetable:
id - Primary Key
price - incremental price
description - item description
then set the radio buttons to pass the id value for the price description combonation, and use a lookup recordset to return the price and description for the selected radio button.
In the add to cart button, bind the price increment column to the price column from the recordset, and bind the description column to the description column from the recordset.