As a coupon shopper, I have stockpiled a LOT of laundry detergent. However, as a prepper I'm a firm believer in back ups! I've used the following recipes, liquid and dry, and found them reasonable alternatives to store bought brands.
Consider stockpiling these ingredients. They are reasonably inexpensive and the detergent can be made even off grid.
Homemade Laundry Soap
4 C water for sauce pan 1 bar grated Fels Naptha soap 1 cup Arm & Hammer washing soda 1 cup 20 Mule Team Borax 4 1/2 gallons water 5 gallon bucket
Put grated Fels Naptha in saucepan and cover with water. Heat on low until dissolved. Fill bucket with hot water and add soap. Stir to combine. Add 1 cup washing soda and 1 cup borax and mix well. As it cools, it will thicken. If mixture becomes too thick, add hot water to thin it to desired consistency. May be used immediately. Mix well before each use. Use 1/2(normal) to 1 cup per load (heavy).
(Cost per load = approx. 4 cents!)
Homemade Powder Laundry Soap
1 cup grated Fels Naptha soap 1/2 cup Arm & Hammer Washing Soda 1/2 cup Borax
To make a large batch, grate 6 bars and add 3 cups washing soda and 3 cups Borax. Mix and store in airtight container.
One more thought...I've pre-made several batches of the dry detergent and vacuum sealed it in Food Saver bags. One draw back on the dry detergent is that you can find that it doesn't fully dissolve in the wash cycle. I've actually taken my stored dry detergent and created the liquid detergent when I needed it rather than storing 5 gallons of detergent long term.