It is not the size or shape that confuses him, but the inability to find a coin that will transcend all value, a Matbe'a that will dominate the world. G-d shows him the coin that emanates from underneath His throne, the seat of all true worth. This Shekel is made of fire, the one element that consumes everything it touches. While common values are flimsy and transitory, the Matbe'a Shel Aish overpowers the standards of society with a different vision of worthiness, a new measure of importance. This heavenly perspective subsumes all worldly constructs, and man suddenly realizes that the pleasures of his world are destined to fade.
Market price is determined by supply and demand.
The sole determinant of current value is the desirability of any particular article. For this reason, millions of dollars are spent annually to convince consumers that they absolutely must have items that they really don't need. These artificial supports keep the economy churning, producing ever greater profits for those ensconced within the system. If ever man will come to his senses, and realize that he can live without this year's new and improved model, profits would deflate, the economy will come to a halt, and we wouldn't have bread to eat. The Jewish people have their own system of commerce.