PLZ HELP IM HAVING A CLOTHING CRISIS!!!! 10 points?

Im 15 and going into my sopre year in high school.. I Want to Start the uear with a bang.. I've Searched Evrywhere for "The Back To School Must Haves".... Im pretty preppy but then again im a little of everything... I like clothes from places like aero and hollister.. I need Affordable clothes....So Tell Me The Essentials for back to school.... and where i can find them cheap... THANX