Three Little Embrys Laundry Powder
1 cup washing soda
1 cup Borax
1 bar soap
1/2 cup baking soda
Grate one bar of soap (~5 oz) with a cheese grater or food processor. Mix ingredients together and stir thoroughly. Store in an airtight container. Use 1-2 tbsp of powder per load. Makes ~32 oz of detergent (32-64 loads).
Arm & Hammer Washing Soda, 55 oz - $3.24 ($0.47/cup)
Arm & Hammer Baking Soda, 4 lb - $2.12 ($0.27/cup)
20 Mule Team Borax, 76 oz - $2.98 ($0.31/cup)
Ivory, 3.1 oz - $0.25 ($0.40/5oz)
Dr. Bronner's, 5 oz $4.04
A batch using Dr. Bronner's cost $4.95 ($0.08/load) whereas Ivory would cost $1.32 ($0.02/load). We had been using Tide Pods ($0.25/load) and since we do about 10 loads of laundry a week, not counting diapers, the savings is pretty substantial. For comparison, the cheapest detergent at the commissary is $0.12/load.
Basically, we can save $120 a year by making our own detergent that works just as well as Tide.