Product Package Weight And Price

Where to add it? Or we should enter the product weight packaged?

Also, what is the use of the Freight entry, if there is separate shipping cost?

How do you calculate the price of the packaging itself. If the Product costs $5 and the package another $1, this is 20% discount if we do not include the price of the package.

There is also handling cost, always - it takes time, gas and nerves.