This is a nitpick, but I suspect the author doesn't know what "TCO" means. It doesn't mean "all in purchase price", it means... "total cost of ownership"[1]. The base raspberry pi[2] already costs between $25-$35. Add in shipping, cost of cables/charge/case (pictured), the purchase price alone would likely exceed $35. If we add in the cost of 5 years of power (I'm using 1W) that would definitely push us well beyond $35. And this is all before going over the biggest line item: cost of labor. It might be "free" to you, but if you're doing a cost calculation you should at least value it at the federal minimum wage.
This is a nitpick, but I suspect the author doesn't know what "TCO" means. It doesn't mean "all in purchase price", it means... "total cost of ownership"[1]. The base raspberry pi[2] already costs between $25-$35. Add in shipping, cost of cables/charge/case (pictured), the purchase price alone would likely exceed $35. If we add in the cost of 5 years of power (I'm using 1W) that would definitely push us well beyond $35. And this is all before going over the biggest line item: cost of labor. It might be "free" to you, but if you're doing a cost calculation you should at least value it at the federal minimum wage.
[1] https://en.wikipedia.org/wiki/Total_cost_of_ownership
[2] https://en.wikipedia.org/wiki/Raspberry_Pi