The Cost and Supply of Goods

Firms do three things: purchase productive resources from households/firms, transform them into a different commodity, and sell the transformed product/service to consumers. In a market economy, all these steps are up to the firm's discretion (after all, in privately owned firms, it is the owners who invest their funds and are in other words risking their financial future). Incentives depend on the organization of the firm. The owner's who risk their wealth are the residual claimants, meaning that they receive the excess of revenue over costs. In this case the incentives are aligned such that the success of the business is in the best interest of the owners i.e., they will see to it that managers/employees use resources efficiently and produce value greater than the costs. This sort of productive activity can be organized in two ways: contracting and team production. Team production reduces transaction costs but lowers the incentive for individual employees to contribute their best (so incentives like bonuses are set in place to keep employees from shirking), whereas contracting could, in theory, be the only way to accomplish production. However, both methods are used in actual production.

One Does Not Simply...

With regard to choosing a major, I've come to the realization that: One does not simply go to George Mason University without taking a course Economics. 

If you're looking for a reason why, let me give you a few: Tyler Cowen, Peter Boettke, Walter E. Williams, Brian Caplan, and the list goes on. 

...What about the Mercatus Center, or the Institute for Humane Studies?

If you haven't guessed it, there is strong orientation towards liberty (and individual rights) on the Economics side of things here (if the ECON course on Austrian Economics is any indication). 

For those sympathetic to the cause for freedom, it should mean something that the largest college in the state of Virginia makes the list (with about only 20 other institutions) for places where one might take a formal course on, say, Austrian Economics.