The author would benefit greatly by reading Karl Marx's Critique on Political economy. In this article they are mixing the notions of use value-cost, price-money.<p>One example is open source. Open source code has by definition 0 exchange value, thus 0 price. It is insanely usefull but you can't make a single cent selling them. This is no paradox, and one can inderstand how that works by reading the book.