product with fixed price and required purchase

I am using version 1.3.9g. I want to have a product displayed first in one category which is a fixed price and which is required for purchase of anything in the category, so I don't want the person to select it, I want it to add to the total of purchases which are made. How do I do that?

Can you add the product to each item and combine the price?

The objective is to establish clearly that there is a fixed priced item which is always part of any transaction. This is for an organization which wants to make Paypal payment available as a courtesy, but wants to recover some of the cost of the transaction. We want that purchase item to become one of the items to purchase, but do not want it as a choice, but rather as a requirement.

I can see I could do so under shipping and handling, but we want the cost to be identified at the very beginning of the purchase process.

Mark