How many kilos of bread can I produce with one kilo of flour?
In my experience, it doesn't really save money, but it's still worth it because it's fresh and better than store-bought at the same price.

For me, 1kg of all purpose flour yields 1.6kg of bread (as two loaves). Each 13x4x4" (Pullman) loaf weighs about 800 grams after cooling and yields between 24-30 slices depending on thickness. The cost per loaf is under $1.00, and includes all ingredients, tax, and electric for mixing/baking/slicing.

I've made a few hundred loaves based on variations of this formula:

                      %  grams   cost  cals fat protein sugar sodium
all purpose flour    100  500   0.417  1833   0      50    17      0
    instant yeast    0.8    4   0.067    16   0       0     0      3
  nonfat dry milk      4   20   0.203    70   0       7    10    109
       canola oil     10   50   0.072   429  50       0     0      0
            sugar      4   20   0.019    75   0       0    20      0
             salt      2   10   0.006     0   0       0     0   3933
            water     56  280   0.000     0   0       0     0      0
      dough total  176.8  884  $0.783  2422  50      57    47   4045


To be clear, I no longer use a bread machine. My answer focused more on how much bread can be made with 1kg flour. The Pullman loaf pan was $25, and the electric knife was $20. So for 300 loaves, that adds 15 cents per loaf. The mixer and oven are used for other things besides bread, so I don't really consider them in the overall cost per loaf.