Our dishwasher sucks. It doesn't clean up to the top rack, and frequently stops draining, so I hate buying dishwasher soap. I found a recipe for homemade dish powder and gave it a try. It did leave a white film on our dishes, but we have really hard water and it was no worse than the regular soap does.
1/2 cup Borax
1/2 cup Washing Soda
1/4 cup coarse salt like pickling salt
1 to 2 T lemonade Kool Aid or store brand (this is for the acid to help with hard water - I end up using 1/4 cup which is about 10 little packets)