You can take those store-bought cleaning products off your shopping list. Here is a list of basic supplies that can get you through many domestic tasks.
Old housekeeping manuals and books on simple living often talk about the soap jar. This is a place where all those slivers of hand soap go when you are about to start a fresh bar. Pour in a little boiling water and you get a soft jelly which can be used for dishwashing, clothes, or diluted as a spray for aphids that attack your house plants.
This is endlessly useful around the house. Buy a box from the drugstore rather than the tiny ones you get for baking. It is a water softener, can be used as a scouring powder on sinks and bathtubs It's effective and easy to rinse away. It can be used as a coating on ovens to make them easier to clean, as an excellent polish for chrome. It also makes a good tooth powder and can be used in solution as a garden fungicide (half a teaspoon per pint of water).
Salt is a mild disinfectant, and makes an abrasive but benign scouring powder. Keep drains clear with a weekly handful of salt and a kettle full of boiling water.
Clear distilled vinegar