1c washing soda
Use vinegar in rinse if you have hard water
Pour borax and soda into mason jar, cover, shake, store.
Use 2tsp per load! :)
Keep in mind this costs only pennies to make! 20 Mule Team Borax comes in a 76oz box at $3.12 at Meijer in Michigan and Arm & Hammer Washing Soda was $2.79 for 55 oz at Meijer. Both were in the laundry detergent aisle.
I understand you can also get them at Hardware stores or have them shipped to you via Amazon.com links herein.