I have to dig up the ol' college ID, because Sephora is doing a back-to-school promotion this weekend. Tomorrow and Sunday (only), you can flash your student ID and get a free mirror that sticks to your cell phone. I managed to snag one of these early, and I'm surprised by how often I use it. It's a ridiculously simple idea that has made my little touch-ups so much easier. Instead of fishing around in my purse for a mirror, I just grab my phone and take a look-see. So if you're a student, look up the nearest store, run in and get this freebie while supplies last, along with a card with 10 "backpack beauty essentials." Trust me on this one—you will use it all the time. And it doesn't get better than being free!