1. 1 cup of washing soda (not to be confused with "baking soda")
2. 1 cup of Borax
3. 1/4 of a cup of kosher salt
I tripled the recipe in order to fill my container...I would also recommend putting this in a container that is water-tight. Use 1/2 tbsp. in each load and it will not only clean your dishes but it keeps the inside of your dishwasher smelling fresh and, all this, at a fraction of the cost.
Also, where you would normally put some of the "high-dollar" rinse aid I add white vinegar in its place...I use my "Orange Peel Scented Vinegar". This rinses wonderfully without any of the spots or streaks and the vinegar only cost me a dollar. :-)
Shared at http://www.oursimplecountrylife.com/