Since I started doing my own laundry, in college, I've not really known what brand to buy. I didn't think about it too much, and defaulted to whatever I saw at home that I didn't think I would have an adverse reaction to. Fast forward 5 years, and I'm tired of buying laundry detergent.
Liquid laundry detergent:
To make this, you'll have to some hunting at your local supermarket. In the laundry aisle, pick up three ingredients:
Borax (probably Mule Team brand)
Washing Soda (probably Arm & Hammer brand- and be sure to get WASHING soda, not BAKING soda)
Laundry Bar Soap (I use Fels-Naptha. Zote brand is mentioned in other recipes)
These ingredients will be good for many, many gallons of laundry detergent, so you'll be set for a while.
1/2 cup Washing Soda
1/2 cup Borax
1/3 bar soap (grated- use a food processor or box grater to accomplish this)
Heat 6 cups of water on the stove. Add the grated bar soap and stir until melted. Then add the washing soda and borax. Stir until powder is dissolved, then remove from heat.
In a 5 gallon bucket, pour 4 cups of hot water and add the heated soap mixture. Top pail with cold water and stir well with a wooden paint stirrer. Let sit for at least 24 hours. The mixture may separate- stir then add to smaller, more manageable containers than the 5-gallon bucket. As you can see, I've used vegetable oil bottles, milk gallons, and any plastic container that's easy to pour.
Shake container before using and use 1/3-1/2 cup per load.
I haven't done a cost savings breakdown, but others around the web come up with 1 cent or less per load, vastly better than store-bought alternatives. We've been using this soap for about a year and have been happy with our clean clothes!