it cost around $30 for me to get all my supplies, about 20-30 minutes to make the soap, and took a year and a half to go through it all. for a family of 6. with a husband who bike commutes and does lots of dirty house projects. with FOUR kids. seriously. about $2/month to wash all the myriad of laundry that comes down the shoot.
you will need an empty 5-gallon bucket with a lid. like an old CLEAN drywall mud bucket or something. just giving you warning so you don't get into this recipe and figure out you don't have a big enough container to mix your laundry soap. :)
erin's laundry soap
2 - 4 lb boxes baking soda
2 - 3.75 lb boxes washing soda (i buy arm and hammer washing soda, it's a yellow box...and it is IMPERATIVE that you buy washing soda)
1 box borax (i think there was only one size available)
1 container dye-free oxi clean (the round container with the lime green lid)
9 bars fels naptha soap
start by grating the bars of fels naptha soap. this is most easily done with the small grater attachment for a food processor. i grate three bars at a time and then empty the bowl. after all nine bars are grated, i put the blade back into the food processor bowl and make it into a finer powder. this extra step is worth it...i have done it without the extra processing and the soap doesn't work as well.
next, if you want your laundry soap scented, add 40 drops of essential oil (i like to use lavendar for laundry) to each of the boxes of baking soda.
now, start dumping boxes and grated soap into the 5-gallon bucket. once everything is in the bucket, put on the lid tightly and start rolling/shaking/etc to mix the soap. andy picked up the bucket and gave it some really nice shakes after he heard me flopping it around. :)
use 2 T (1/8 C) to 1/4 C per load. you really don't need very much. this soap is high-efficiency washer safe. i have been using it in my kenmore elite calypso machine for almost two years and have had no problems.
for whites, sheets, or other grimey things, i add 1 C of white vinegar to the fabric softener dispenser to help get out any additional residue. you can scent your vinegar by adding 40 drops of essential oil to a 1 L bottle of white vinegar...the cheapest (and best) fabric softener you will ever use. you can whiten by adding 1 C of lemon juice to your bleach dispenser. get rid of bed bugs and dust mites by adding a couple drops of eucalyptus oil to the detergent.
happy washing. :)