Here's a great idea that was shared with me recently. Get more for your money with your dishwasher detergent. Combine equal parts baking soda, your favorite powder detergent, and washing soda. Here, I used Seventh Generation Free and Clear Detergent, but I find other detergents work much better. To really stretch your dollar, try using $ store variety!
Find a container (preferably with a lid), and combine ingredients. Shake/mix well.
For a full load of dishes I use 1.5-2 Tablespoons of my mixture. Instead of paying for a small bottle of liquid rinse aid, put vinegar in the designated rinse aid compartment. It will help you dishes sparkle!
*Note: If you have liquid detergent on hand, you can combine the washing soda and baking powder and mix it with detergent in the dishwasher. Just use 1 Tablespoon of the washing soda and baking soda mix with 1 Tablespoon of liquid detergent.