Ten Principles of Economics- A Brief Discussion about Microeconomics and Macroeconomics Micro-Economics Principle-1:  People face trade-offs. Micro-Economics Principle-2:  Everything has a cost. Micro-Economics Principle-3:   Rational people think at the margin. Micro-Economics Principle-4:  People respond to incentives. Micro-Economics Principle-5:  Trade can make everyone better off. Micro-Economics Principle-6:  Markets are a good