alt Hacker NewsGiven later advances in smartphones, I think I'd rather have a little QR code or NFC sticker that encodes "saved product 123".
Then a platform-agnostic open-source app on your phone pulls up the matching entry (e.g. "toilet paper" or whatever) and gives you a fast way to go to the previously-ordered products' page.
Then you aren't bound to any particular vendor, you see prices before ordering, and you could use the same system for other kinds of locationally-bound notes or tasks.
While that does sound more open & flexible the button originally was tied to a specific account with purchasing power + notifications of the order in general (with price).
There is still the issue of who is paying for said item and building an open platform that allows another individual to use my funds at the press of a button would require a lot of investment (identity, trust, limits, etc) though I do see the value you are proposing showing a "mini market" to select from.