Mine isn't all that fancy, lol.
The focus has been more on the digital realm, which is important, but would something focused on physical purchases be useful? I could see that getting unwieldy as well, so perhaps something like this would be better as a wiki page
It could be interesting. The easy part: put everything that is not Amazon, the hard part: every country has its own variant.
Oh, that's a good point - and ideally, folks may prioritize shopping locally or at regional chains. "bookshop.org" is good for connecting to your local bookshop, but not every industry has something like that.