One of them is the notion that wealth is a fixed amount. This is called the “zero-sum game” fallacy. It implies that one person can only become wealthy by other people becoming poor. Entrepreneurship and the right institutions in place (especially the rule of law) are the factors that nullify that myth.
Another misconception is how the economic value of something is determined. It’s not through the labor that creates an object or service. Rather, it’s through the subjective value that is attached to the good or service by hundreds of thousands of people in a market place. The price of a book I write is not determined by how many hours I spent working on it, but by what people are willing to pay for it. And what they are willing to pay for it is determined by how much they want it compared to all the other books, services and goods they want.
Then there is the notion that free trade can only benefit the wealthy or wealthy countries. Again, if you look at the stories of how nations escape poverty, it’s not through subsidies, protectionism and closed markets. Rather, it’s through entering what St. John Paul the Great called the circles of exchange and embracing institutions such as rule of law.
The whole question regarding economic misconceptions is a fascinating one — so much so that we even have a course at Acton’s summer university program on that topic. We address and correct common economic fallacies, and this is something that many people — Catholic, Eastern Orthodox, evangelical and Jewish — find extremely helpful.