Did you know that you can use vinegar, baking soda and Dawn dish soap to clean jewelry, soften clothes, brighten whites, scour surfaces, freshen your fridge, perk up your carpet, clear your drains, remove build up from your hair and more? I mentioned at work that I purchase baking soda in 12-pound bags (for $5.76!) and you would have thought I said I get abducted by aliens every Tuesday night.
These three items, which can regularly be purchased extremely inexpensively, have replaced myriad household cleaners and serve many, many purposes. In addition, they are so much better for the environment and cheaper than conventional products such as oven cleaner, drain degreasers or fabric softener. Rest assured, there are books at your local library that will explain at least 1,000 uses for baking soda and vinegar.
You can start to learn about the uses of vinegar here and baking soda here.