An alternative is to specify generic items (eg. breakfast cereal) and let the program construct a shopping list that most closely fits your criteria (eg. brand XYZ fruity munchies). For each item, maybe offer a pop-up that lists alternatives in descending order, so you are not happy with a suggestion you can easily scan for and select a "next best"? You can then use your shopping list in the normal way.
Maybe it could also offer the option to place the order for you, so it becomes an "ethical online shopping" site? Like any other shopping site, your list could be saved and reused/tailored next time. If the status of any item changes, a suggestion to change brands could automatically be made next time the list is used. Funding could be by negotiating a cut of each purchase with the vendor?
Maybe it could also offer the option to place the order for you, so it becomes an "ethical online shopping" site? Like any other shopping site, your list could be saved and reused/tailored next time. If the status of any item changes, a suggestion to change brands could automatically be made next time the list is used. Funding could be by negotiating a cut of each purchase with the vendor?