It is not wrong. The correct phrase is: "Free trades have mutual perceived benefit or they wouldn't happen." What makes a free trade free is the absence of fo

It is not wrong. The correct phrase is: "Free trades have mutual perceived benefit or they wouldn't happen." What makes a free trade free is the absence of force or fraud, not perfect information. By the way, imperfect information is also called "risk", and risk affects the price of the trade. It's why responsible people can borrow money at lower rates than irresponsible ones. Or why a car that won't start will sell at a far lower price than one that does, even if the repair is reconnecting a loose wire. Or why you'll be willing to pay more for an item from a reputable dealer than an unknown one.