I am a salesman in Washington state and thought I might be able to help out a little.
I do not know who you are purchasing your vehicle from or even where, but when we get our Prius' they have already included the Z1 package (mats, net and first aid kit). Unfortunately they can not be deleted from the vehicle because of weird rulings. If it comes that way, we can not modify it. True, you can get all that cheaper aftermarket and choose the ones that you want. Just do not think of it as the dealer trying to weasle every penny he can because there is all of about $10-15 profit in that option.
Hope I helped.