What a nonsensical argument. Deodorant is a consumable good. In scenarios like this, 40$ for 4 == 10$ for 1, because you consume it at a steady rate, and what you don't buy now you will pay for later

Compare to an extreme example of a market selling one watermelon for 5 dollars, and 5 watermelons for 15. Sure, the latter is a better deal, but I definitely have no use for more than one melon, and the arbitrage opportunity is not worth my time. In the same sense, I and many others do not need more than 1 deodorant at a time and I would rather save my space.

Watermelons are perishable, so that's apples to eggs.

Do you live in a microhome? Deodorant sticks are tiny, surely you can store 3 of them under your sink for months without too much suffering.

Deodorant has a shelf life. If you stock too many, some go bad before you get to use them.

Do you know what that is? I typically buy 4-5 sticks at a time when my local pharmacy has a sale on the one I like, so I buy deodorant like once a year.

Never noticed any problems with them.

> Do you know what that is

Mine is 2 years

But you still need to store all four sticks in the meantime. Some people have extremely limited storage space.

It's not like it goes bad, you will use all 4.