Your parents always told you to eat your vegetables. But if French fries are cheaper than potatoes, cream of mushroom soup is cheaper than portobellos, and a medium pizza is a better buy than a caprese salad, the veggies you can afford might not be so fresh and crunchy. So what if the produce were cheap? That's the question the U.S. Agriculture Department is trying to answer as it launches a test project in western Massachusetts to offer low-income families a 30 percent discount on fresh fruits and vegetables. "There is a lot of very low-cost, processed food products that...