Baking Soda
If you go to a warehouse store like Costco, you can get a box of Arm & Hammer Baking Soda for only 85 cents. How cheap is that?! On that of that, they will not spoil. Feel free to go ahead and stock up on it.
Shampoo
Shampoo is used to clean your hair. However, an off-brand one will be as good as a more expensive one. You can save nearly $2 on a shampoo bottle if you get it from the dollar store instead. Trust us, it is not worth paying so much more money for the name of the brand or a specific scent.