What is the main idea of the passage?

Posted prices reduce the effort and uncertainty of routine exchange by making an offer visible to strangers. (The passage treats a posted offer as shared infrastructure that lowers negotiation effort while preserving choice and exceptions.)

Why does the author describe a posted price as shared infrastructure?

It gives unknown buyers and workers a common starting offer without repeated negotiation. (The seller posts before knowing who will enter, and buyers and workers can then act from the same visible offer.)

What is a “transaction cost” in the first paragraph?

The effort, uncertainty, and delay involved in reaching an exchange (The phrase is immediately defined through the attention, uncertainty, and delay required to reach an agreement.)

What does a visible posted price fail to prove?

That the price is fair (The third paragraph explicitly warns that visibility does not prove fairness.)

What a Posted Price Saves: Level 4 Reading Comprehension Questions

At a market with no posted prices, each sale begins as a fresh conversation. A buyer asks, a seller answers, and both may spend time bargaining. That flexibility can be useful when goods vary or when buyers want different quantities. It also carries a transaction cost: the attention, uncertainty, and delay required to reach one agreement.

A posted price turns part of that conversation into shared infrastructure. The seller states an offer before knowing who will enter. Buyers can compare several offers without opening a negotiation at every stall. Workers can complete routine sales consistently, and a person who dislikes bargaining can still participate. The tag does not remove choice; it makes one possible deal visible to strangers.

That visibility can widen a market, but it does not prove that the price is fair. A seller may still change prices over time, offer a discount for quantity, or describe features that a number cannot capture. Buyers may value service, quality, or trust as much as the lowest figure.

The economic gain is therefore not simply cheaper goods. A posted price reduces the effort of discovering whether a basic exchange is possible. Like a common measure or a labeled route, it lets people begin from the same public signal, then spend their conversation on exceptions that actually need it.

Comprehension questions