During your review of previous comments, did you observe the context in which "cost" is discussed? Was it in amorphous "value of your time" concepts or was it

During your review of previous comments, did you observe the context in which "cost" is discussed? Was it in amorphous "value of your time" concepts or was it in concrete, "This cost 1.5 million dollars that we paid to a company"? What you'll find is that the "cost" reference is to a payment made, not to an estimation of time value. In this sense, "sending an email" does cost $0.00, as you can do it without paying, for example, Google.