Insomnia Cookies is sweetening the back-to-school season with a special offer for students and teachers this month. 

The late night cookie bakery chain is giving a free six-pack of Classic cookies with any $5 in-store purchase to anyone who mentions the deal and presents a school-issued ID. The offer is available now through Friday, September 1 at 3 am at participating locations nationwide. 

Founded in 20 years ago in Philadelphia, Insomnia Cookies has grown to more than 240 locations across the country. The bakery offers a wide variety of cookies, ice cream and other sweet treats in-store, for local delivery and nationwide shipping.