Its been a good year now but I remember high school lunch. You could bring lunch with you but the cafeteria was open from 1st period till the end of 7th period, although some friends who are still their say it now remains open until half an hour after school ended. When I was a freshmen the food was horrible for you, but absolutely delicious. Oh how I miss those french fries....
. Starting in my sophomore year our school adopted what is called the Wellness policy, I'm not sure if they were forced to by law or not. Essential all kinds of limits on things like calories, fat, sodium, ect. were put in place. All kinds of bread were replaced with whole wheat (including burger buns and even pizza), a salad bar was added, things like that. Essentially offering a healthier variety of foods. There is a decent selection, they have burgers, pizza, calzones, certain pre-made sandwiches, and of course the salad bar. Everyday there was a special lunch that rotated on a regular basis. Also they had a mini-deli style thing where you could get sandwiches or wraps made to order. There was also a variety of snacks such as cookies, some ice cream, pretzels, fruit smoothies, all of it usually of the low fat variety. Hope that helped!
Edit: Oh, and as for price, it varied but most of the food was cheaper then you would find it outside of school. Maybe 10%-20% cheaper then an equivalent item in the real world.