Pricematching at Petco/Petco.com?

they ship by total amount your purchase comes to, not by weight or size (although they may charge extra for larger shaped objects) so they can lose or gain very little from shipping charges.
 
Shipping fees are more than what the carrier charges to deliver the goods. The shipping fees are set to cover the vendors labor/overhead/materials to prepare the goods for shipping, plus the carrier charges to deliver.
 
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