I believe a worker should be able to afford what he creates. A coffee shop worker should be able to afford the coffees sold there even if he only earns £8 an hour. A food delivery driver earns £2-£3 per delivery when delivering food. He should be able to afford delivery of takeaways.
I propose pricing be conditional on income levels. Have multiple brackets of pricing.
For people earning very little, less than £12,500, the prices are adjusted to be 27% of the full price, so a coffee costs them £1. This is so that they can afford the produce and they are paying only the cost to produce.
If you earn more than £12,500, the price scales up accordingly.