If they weren't the #1 purveyor of junk mail I would agree with you. It costs $0.71 to send a card to a family member, but much less than that for a scammy marketing company to mass mail junk that will go straight to the trash.

Eh, if the post office - which is a pretty efficient operation - thinks it costs $0.61 to mail a postcard, it probably costs Amazon more than $0.25 to ship someone a lime.