That is an excellent point.
It is certainly a side benefit of having a stock of items commonly used every day.
When we need something we take it from our prepper stores.
Next time it is on sale we replenish the stock.
Another thing is, Keep your automobile in good condition! and full of gas. And always have some cash on hand!
When the power went out here, after a day we needed more ice, because it was so hot. We went out to the car, and found the oil-light on. We were afraid that driving it would damage it, and walked to the nearest store to buy oil. But, they had no power either, and were only taking cash. (We had none.)
Luckily, one of our neighbors had a car, and she was able to carry us to where the power was still on, and credit/debit cards still worked.
I will never forget grabbing the last two bags of ice in that store - one for my neighbor, and one for us; and then having a lady who saw the ice in my shopping cart ask me where in the store I had found it, and acting as if she would demand that I give her one of the bags.
Fortunately, before we checked out, the ice was replenished; and everyone was happy.
But, it was definitely a ‘lesson’.
JT