3 best options: Louis Vuitton, Tumi, Coach for a modern/understated school or everyday errand backpack. But those are suggestions for guys. I’d rather see girls carrying totes or oversized bags. If you were to take this route I’d suggest an LV keepall MM in a damier canvas ($870), or maybe a canvas Longchamp tote or one of their backpacks for a cheaper route. If you really want to go all out, a Celine cabas tote is really popular for girls AND guys on college campuses I think; or you have the LATEST season Celine SEAU bag if you’re serious about the word “designer.” The astoundingly flawless Italian powerhouse that is Bottega Veneta has great messenger bags, but they also have the surprisingly cheap (for BV) Scolpito tote ($920) for women that is price. If you want to rephrase the question with a price range, please ask again.