Here are some tips for making eco friendly and really cheap natural cleaning products.

1) Baking soda cleans but also gets rid of odors.  (That is why we use it in the frig) Sprinkle on the carpet and vacuum it up. Mix it with Sea salt and it is a good scouring cleanser.

2) Vinegar removes grease and dirt. White vinegar gets rid of carpet odors.  Vinegar, baking soda, and water can make a good all purpose cleaner.

3) Citrus juice and peels like that of lemon are good for freshening up rooms.

4) Borax (20 Mule team) cleans, removes stains and disinfects. A good bleach alternative.

Treehugger has an article on cleaners