Ma'am, you may like to read: https://www.systemsofexchange.org/post/the-quakers-and-the-origin-of-fixed-prices

Fixed prices for buyers are a very doctrinaire Classical Liberal thing. 

Marxist-Leninists Communists were for fixed prices, nearly as much as Classical Liberals.

If you feel, as I do, that discriminatory pricing is an abuse of market power (even if for non-market ends), then we are in the minority, and many of our fellow-travellers really are Communists.