You didn’t figure in the cost of the spray or butter or shortening for greasing the pan, the cost of running the oven for an hour, and the cost of the water for washing the pan and mixing bowls, sifter, and mixing spoons.
I agree that it was more expensive for me to make bread than buy it. But then I stopped eating bread for health reasons (sob!) and that’s the cheapest course of all.
I thought the butter was in there? But the bread makers are pretty efficient energy wise, especially in the winter when any excess heat goes to heat the house. The person who wrote that said they deliberately omitted the water cost as negligible (which it would be here even for a season of use).