This formula is earth friendly/green, and CHEAP. Here's the condensed instructions of the formula created by Lynn Siprelle of The New Homemaker:
Mix the following ingredients in a plastic container with an airtight lid (one you can shake):
1 cup borax
1 cup baking soda
1/4 cup salt
1/4 cup citric acid (Unsweetened Lemonade-Flavored Kool-Aid can be used also, but be sure to avoid any other flavours due to their food dye content)
30 drops a citrus essential oil of your choice
Shake the contents until thoroughly mixed.
Dole out the mixture (one Tbsp per cleaning receptacle) into your dishwasher and use as a light kitchen scouring powder.
Taken from Apartment Therapy.
****** ETA REVIEW ******
I made this powder shortly after we moved into our place and I really like it. It's taken some getting used to, though. For example, if I use too much I get a thin film on my glasses. Not enough and food particles stick to everything. I still have to use a rinsing agent. Next time I will not add as much essential oil. I expect to fiddle with the recipe and get it just right (and minus the film). Overall, worth the ton of money I've saved on this stuff. And green, too.