It is not as cheap as the make it yourself soaps else where in FRUGALITY section described, but it is cheaper than most all others named, and much better for Mother Nature.
I would just like to throw my two cents in and say that I also use soap nuts with great results. Not only for laundery, but for hand/body wash, cleaning table tops and floors and such.
Becky, I'd love to hear about your experience using soapnuts on your hair. I tried them recently and liked the results somewhat after the first wash, but every time I washed my hair seemed a bit less clean and I gave up. I'm not sure if there's an adjustment period like people experience when they go shampoo-free, if I was somehow doing it wrong, or if soapnuts just don't work for my hair.