Maybe I should be more specific. For our shipping, I want to have one component of the shipping charge be the actual charge we have to pay to USPS or UPS, and the other component to be the shipping materials (we ship almost nothing but glass, so it has to be double boxed - so materials get pretty expensive).
I know I could just add an amount onto whatever UPS is going to charge us, but I was thinking that it might be kind of nice to itemize it for the customer - and be able to tell that the cashier has added the Materials expense.
My first inclination was to create a Product for the Materials, and charge that way. But that Handling charge is just sitting there - for every single transaction - and not doing anything. I thought maybe I could put it to use, but I'd need to be able to find the results of its use somewhere.