A few months ago, I started making dishwasher detergent at home. It's really simple: equal parts washing soda and borax powder, well mixed, with a few drops of essential oil for aesthetic value (we use lavender, mostly because we already had it). It works pretty well - maybe not as well as the Method tabs we were using, but it's a hell of a lot cheaper.
Emboldened by this modest success, I decided to try making my own laundry detergent. The recipe I found is pretty basic: a cup of washing soda, a half cup of borax powder, a bar of soap, and 13 quarts (3.25 gallons) of water. It's cheap, too - it works out to roughly 3¢ a load. Three cents!
I was going to splurge on a bar of Dr. Bronner's soap, but I found a bar of Bee & Flower sandalwood soap on sale for 79¢, so I went with that - in the future, though, I may use some liquid Dr. Bronner's soap, which we buy by the gallon, since I now have an idea how much soap to use.
Basically, you bring a quart of water to a boil or near-boil, mix in the grated soap, stir it until it's a uniformly soapy mixture, and then dump it into three gallons of hot water, which you should have in a five-gallon bucket. I used room-temperature water, and I don't think it made a difference.
After mixing the soapy water into the other water, you add a cup of washing soda, stir for a bit, add a half cup of borax powder (if you feel like it), stir some more, and that's it. It has to "cellar" overnight, preferably with a lid on the bucket, and then it's ready to use.
I just finished making it (took twenty minutes, tops - less time than it's taken to write this post), so I have no idea what the finished product will look like, or how it will work - but I'm going to put it to the test tomorrow, and use it to wash a load of Jack's diapers. If it can get them clean, it can get anything clean.