I dont think power store shipping will be able to do what you want to do, it wont support the type of shipping settings you are trying to implement.
For example, there is not a way to offer shipping that applies to prints which by passes the shipping for the cards.
I think the closest you will find is to set a Shipping / Handling rate on the Products update page.
Go to update a product and on the Additional settings tab, you can set a Shipping Handling rate for the product.
the shipping rate you enter will be multiplied by the quantity ordered for that product. this will allow you to set a per item rate for Cards, and a separate per item rate for prints.