Why does pon ask where I want to buy an item?
Because shopping locations are the heart of pon. Almost everything pon takes off your hands depends on them: how your list is grouped, the learned order along the shelves, the reminder in the right place. So it is worth understanding once what pon does with them.
What matters is the difference between two situations: planning and shopping.
While planning, your list is grouped by each item's main store. Put milk on the list with Walmart as its main store and it sits under „Walmart“ — neatly separated by store, just as you planned it.
An item can have several stores. In the item details under „Where to buy“ you add, alongside the main store („primary“), as many „Alternatives“ as you like — Kroger, Target and Costco, for example. It simply means: I can get this there too.
When you shop, that pays off. Enter a store pon knows and its section moves right to the top — and into it goes everything you can get there: the items with that main store, every item that lists it as an alternative, and every item without a fixed store. So right where you are, you see exactly what you can pick up here, in one group and in your learned order. Nothing to re-sort, nothing to filter, and no need to decide in advance where you will buy. (One exception: items with an offer reminder stay with their main store — that is where the offer applies.)
Leave the store again and everything returns to the planning view: every item is back with its main store. Nothing is moved permanently — the reordering only lasts while you are there.
You do the work exactly once. What you enter once, pon remembers on the product; next time it is already preselected. And most of the time you do not have to enter anything — pon learns your stores and alternatives by itself while you shop.
And „Any“? Still possible, and it really does mean anywhere: from the hardware store to the supermarket to the pharmacy. While planning, such an item has no store section, no place in the learned order and triggers no location reminder. Standing in a store pon knows, it is offered to you there all the same — but the benefit while planning and reminding is gone. So choose „Any“ deliberately, not out of convenience.
A word on trying it out. If you are coming from another shopping-list app, this feels unfamiliar at first — there you enter items and sort them yourself. Give pon two or three shopping trips: allow location access, let it name your supermarkets, and do not be shy about adding several alternatives. After that the list does the work, not you. That is exactly what we mean when we call pon the smart shopping list.