As for Formula? You can't just change to whatever is cheapest that week.
Then stock up, and seriously? Their shelf stocking doesn't work that way. Any SKU ordered (other than food stuffs and specialty seasonals) are stocked for, at least, one month in any given location before long term stocking is decided on
My experience is otherwise. Maybe in your experience through multiple brands is that they are all the same, but your experience is equally limited.
The simple fact that my experience says otherwise, however, does disprove yours.
> Then stock up
On diapers?
I can't believe you have children and would "stock up" on diapers. Kids grow.