One ingredient worth buying in bulk is bicarbonate of soda (baking soda). Besides being an essential ingredient in treats like muffins and banana bread, it has plenty of uses throughout the home. Here are my top ten:

Fridge and freezer
Bicarb absorbs odours. Place some in an open container in the fridge and replace it every couple of months. Also, give it a quick stir from time to time.
Dry bicarb on a damp cloth will clean your fridge and freezer. Rinse with clean water.

Sinks and drains
Put two to four tablespoons of bicarb into sinks & drains each week and flush with very hot water.

Hairbrushes
Clean hairbrushes and combs in a bicar and water solution.

Burned-on food
Soak pots and pans in bicarb and water for 10 to 15 minutes, then scrub. For badly burned-on food pour a thick layer onto the bottom of the pan. Add enough water to moisten, leave overnight and scrub clean the next day.

Grease and dirt stains
Add a bicarb and water paste (I add a bit of lemon juice if cleaning something white - fantastic on white takkies/canvas shoes) to a grease stain, leave for a while, then wash. Alternatively, add bicarb to the washing water or half a cup to your machine wash load.

Garbage cans
Using bicarb to clean and freshen garbage cans.

Bee stings
Apply a bicarb and water paste.

Bug bites
Apply a bicarb and vinegar paste.

In the bath
Add half a cup or more of bicarb to your bath to relieve sunburn and skin irritations. It also helps soften your skin.

Ashtrays
Dry soda in ashtrays reduces odour.

Need even more reasons to buy bicarb in bulk? Here's a list of sixty one uses.

Another great ingredient that can be used throughout the home is salt. Read more here.

Image source: Cosmic Scoop.