In-season fruits and veggies are less expensive and have more nutrients than produce that has suffered through days of interstate—or international—travel.
Here are some great resources:
Of course, there’s an app for that: Locavore.
The American Heart Association’s website has a whole section devoted to Healthy Kids with great articles like Healthy Snacks Under $1.
And the Mayo Clinic children’s health website provides nutrition guidelines for children according to age and gender.