It depends on the kind of bread you make and how serious you
You can spend anywhere from $25 to $200 on a bread machine.
I like various types of bread, and ended up buying a cheap Rival bread machine ($40), used it for a while, then decided I wanted something more. I now have (and am actually on my second) Zojirushi bread machine. They cost about $200 but are very flexible, have dual paddles, can be custom programmed, and do a great job.
The first one I had lasted about five years. I make bread weekly, or twice weekly.
Here are my financial calculations:
Cost of a loaf of 'good' bread: $3-$4.
Cost of ingredients to make bread: About $.60. Cost of electricity to bake bread: $.15. Cost of loaf: $.75. Note: despite the rise in the cost of flour lately, I buy flour by the 25 pound sack. Typically I will use 12.5 ounces by weight of bread flour and 3.5 ounces of oatmeal, or whole wheat flour. The $.75 estimate for cost of materials includes yeast cost, which I buy by the pound from Sam's Club and/or Costco. I discount the cost of water, as it takes 10 ounces of filtered tap water , which has a negligible cost.
Assuming a $3.25 cost for a loaf, I "save" $2.50 per loaf. This means that the cost of the bread machine will be made up in 80 loaves of bread, or about 1+ years.
Obviously, your mileage may vary. It's quite cheap to bake bread if you use a mixer and/or knead by hand. But I know that I can put the ingredients in, switch it on, and in 3 1/2 hours have a loaf of bread with no effort other than weighing out the flour and other ingredients. If I had to take the time to do things, I wouldn't do it.
There are also some really good bread recipes to make in a food processor.
This is a long answer to a short question, but I'd have to distill it as follows: You have to do what works for you. I have explained my logic. It works for me. it doesn't work for everyone.
Nate