Would this be Legal?

Here’s a question I need answered to fully understand the failure of the American health insurance system:

General Motors announces it will be selling automobiles in a new way. It will no longer sell cars to just any individual. Instead, GM will sign contracts with employers. If you work for a company that has signed a contract with GM, you can buy the car at regular price. If not, it will cost three times as much. Would this program be legal under existing commercial law?

Let me add a corollary: Is it even illegal for a private seller to charge different prices for a product based on age, or race?