"Soygate", or should we warn the user when prices change

[monsieurtanuki]

Problem

Yesterday I bought soy milk in a shop I visit very often.
I bought the same product 2 weeks ago, and it costed 0.88€ then. Yesterday it was 1.15€, which is a 30% increase!
Perhaps it would make sense to warn the users when prices change in a specific context - e.g. same shop, same product:

• when they input the prices - "hey, last time you bought it it was 0.88€!"
• when they open the app - "hey, be careful, in this shop you visit this product price changed from 0.88€ to 1.15€" or "hey, it looks like they discount this product in this shop you visit"

Proposed solution

Probably to be developed at least partially on the Prices server.

Additional context

cc. @raphodn @raphael0202 @teolemon

[teolemon]

And on price reductions within a given radius potentially.

[monsieurtanuki]

@teolemon We could even somehow prepopulate the prices (or offer a "copy price" button): "oh, that soy milk in that store? Costed 0.88€ last time"
[Edited]