What grade of high school are you talking about. Around here we have high school which is grades 9-10 (about 1400/school/6 or so schools I think) ) and Senior High School which is grades 11-12 (about 2500/ the 3 schools)
9-10 cannot leave campus and have lunch at school, they either bring it or buy it. Lunch "pails" ( Ive not heard that term in YEARS) are a no no... a brown paper sack is sufficient. Most boys have some sort of basic backpack, backpacks are not allowed in the classroom and must stay in the locker. You plan when you stop by your locker to switch out supplies/books, etc. Most kids have a basic binder and the school sells an agenda for them to keep up with assignments,etc.
11-12 is open campus, most driver to school and they are allowed to leave campus for lunch. The option of the cafeteria and brown bag is still available. Most boys have a dark colored basic backpack. Girls usually have a large bag of somesort. My daughter prefers the accordion type folder with several sections and she has all of her classes labeled, keeps papers organized, etc.
My suggestion on day 1 would be to have a basic spiral with pencils and a folder of some type. Each teacher sends home a lost of supplies and the curriculum layout for the semester. Most of the time, there is a good grade involved if you bring supplies in to the teacher's recommended time.
Let your son be the guide and purchase the main things AFTER he has been at school a day or 2 so he gets a feel for what is "in" and he makes the choices.
NO cartoons, etc.