Single, public, online product and service database provided by the market regulator. Since the country gets income from taxing commerce it's only fair that they also provide discovery service. If you want to sell something on the market you have to enter it into this database, with the up to date price and relevant documentation.

Consumers can access the database through provided UI or through 3rd party tools using this database API.

Retailers could always highlight high value products they are offering within their storefront (without being compensated by manufacturers to do so; that would be a scam ad).