Why can't I sell stuff at school?

i guess that is really up to your school principal. say you rephrased your proposal to ask if you can set up a desk to advertise your bags, and then anyone interested can say hey can you reserve this one for me? and then you can get the money and they can get the bag in the hall or while you are at your lockers. so the getting the money is more under the table like how kids at my school exchange money for drugs or alcohol or for some nerd to do their homework - none of its allowed but it can easily be done off the record (and in public sight since homemade makeup bags are not illigal) if a teacher saw you selling one to one person i dont even think you could get in trouble for saying i made this bag and sold it to my friend.