I do this and love it - keep a giant vat of it on hand, some in pretty glass jar on the washer, and the rest stored in a bucket in the crawl space until needed. Costs me about $20 every six months for all the stuff, as opposed to around $11/month for liquid detergent. I love the smell of it, it's easy to use, and saves about $92/year - pretty much a no-brainer. :)
5 min DIY Laundry Soap: Grate two bars of Fels Naptha, then run the blade in your food processor that turns it into "powder." It won't be quite as fine as real powdered soap, but very close. Then add two cups of Borax and two cups of washing soda. It only take TWO TEASPOONS to do a large load. I have a soup spoon that holds two teaspoons that I use to measure. -- The hardest part is thinking that two teaspoons will do the job, but it does!
Puree fruit of choice, herbs, or zest from the flesh of citrus. Divide soap equally among three empty containers (not shown). Add 1 teaspoon of each ingredient at a time until desired amount & color are achieved (color darkens as it sets). For berries, add only 1 teaspoon if you want the soap to remain clear.
Do you make your own Homemade Laundry Soap? Do your friends and family think you're kinda crazy? :-) Give them a pretty sample jar of your homemade soap to try for themselves as a Christmas gift. They will soon see the light! ;-)