The concept of the price of milk is sometimes used (perhaps semi-humorously) as a way of distinguishing how detached the wealthy are from the reality perceived by the less wealthy. This is characterized by people who either do not read the price labels on their food or have others to do their shopping, and hence are unaware of the monetary cost of basic necessities.
This has resulted in the titling of at least one regular interview slot ("How much is a pint of milk?" in the semi-imperial based UK) in which the last question is always "And how much is a pint of milk?". The majority of famous (and generally wealthy) interviewees typically have (or pretend to have) no idea of the correct answer, presumably unlike the majority of the readership.