I don't make soap, but we do make our own cloths washing detergent for less than a dollar a gallon. My wife has been using it happily for years.
Get the Zote bar detergent at Walmart and a box of Mule Team Borax. One bar makes 10 gallons. You will need 2, 5-gallon buckets with lid.
Grind the Zote on an old cheese grater. Heat a gallon or so water to boiling and add 2 cups of Borax and the ground Zote to be dissolved in the water. I usually dissolve the Borax first and then the Zote. It seems to mix better this way. When dissolved mix evenly with your 2 buckets , 9 more gallons of water.
Don't try to make it stronger. I used one bar in 5 gallons once and had to cut it out in chunks. That one bar for $1.25 will make 10 gallons about as thick as regular detergent.
