One per customer. Good at Borders Express and Waldenbooks. You've got to belong to its free loyalty program, called Borders Rewards, to take advantage of this deal. The coupon comes with all the usual caveats, listed below.
Caveats: cannot be combined with any other offer, excludes previous purchases, special orders, gift cards, newspapers, magazines, comics, coupon books, eBooks, digital downloads, video games, vinyl LPs, self-publishing programs, tax software, Smartbox products, Rosetta Stone software, shipping, and all electronics.