Household tip on how to save money!

I tried to make my own dish detergent for my dishwasher to try to save some money and it didn't work out so well. The dishes came out with a thick layer of soap scum on them. (we are still trying to get it of some of the dishes!) I did find out however how to conserve on the detergent. Most dishwashers have two spots for the soap. A prewash and the actual wash. The cups for the detergent are huge! To get the dishes clean you don't have to fill them all the way. (I think it is a conspiracy on the soap and dishwasher makers to try and get us to spend more money) I just put one Tbsp of soap in each spot. I have been doing this for 6 months now and have saved a lot. I only buy dish detergent about every two to three months now. It is great!