I've been doing bread for ages. Electrical oven, gas oven and now with a bread machine. I really liked the kneading process, but I have to admit that nowadays the bread machine makes it so easy that...
As for the money (including electricity) used, I do believe this way is cheaper. I do a big loaf (around 1 KG) of whole wheat for 2 weeks. My machine is a 600W, but as you, I think it does not work at full power for the three hours the process lasts.
I have to borrow a friend measuring machine to confirm it though...