1 bar Ivory Soap (or Fels Naptha)
1 cup Borax
1 cup Arm & Hammer Washing Soda
Grate the soap with a cheese grater or with a food processor. Mix together with the powders - Done! 2 Tablespoons per load.
You now have enough soap for 20 loads! And it only cost me $1.48!!! That's 0.07 cents a load! I bought 4 bars of Ivory soap, one box of Borax and one box of Washing Soda and I made 4 batches of laundry soap.
In case you can't find the washing soda - I purchased it from Alice.com but I've also found it at SOME Walmart's.
Update: I love the laundry detergent and will never go back to using store bought. Another thing I learned is that you should make sure to put the detergent into the water BEFORE the clothes or the soap may not dissolve if it gets caught up in the clothing. Warm or hot water works best to dissolve it!