Based on my costs for ingredients and using 2 Tbsp of powder per load, I can make a 25-30 load batch of laundry powder for approxiamately $2.28 plus tax, or .078 cents per load in my front loading washer. Thats pretty good in my books. I decided to start with 2 Tbsp (or 30 grams) per large load and see how the cleaning was, then cut it back until I cannot cut it back anymore and still have clean clothes. The less I use the more value is added to the batch(Can you imagine 60 loads for $2.28???)
Costs: 24 127 gram bars of Ivory Soap (I broke down because of the smell): $10.99
1 3 KG box of Washing Soda: $6.49
1 2 KG box of Borax: $5.49
I grated two bars of soap (254 grams) with the finer blade of my food processor, and then powdered it up with the other ingredients (254 grams of each) until it wasn't going to powder anymore. Because of the soap its a bit of a cakey powder. It reminded me of Ivory Snow that my mom used to buy (smell and texture) I measured everything by weight because its both more accurate and was easier since I have a digital kitchen scale.
My only worry is how it will perform in cold water.