I found this recipe for homemade dishwasher detergent here, the same place I found my homemade laundry detergent. It makes loads and my cost came to just under $20. I only use about 1 TBS per load.
She recommends using a large, very large, bucket or pot. I didn't have one available so I combined all my ingredients in a garbage can liner. I double bagged the garbage can liners so it would have extra support. The double bagged method made it easy to mix everything up by holding each side and shifting it back and forth.
This detergent tends to clot so I put most of it in airtight bags and stored them, then put the rest in a medium size tupperware container, which stays under the sink for easy access.
