If you are a book-lover and aren't already a Borders Reward Club member, I recommend signing up for it. You can do it in store and they give you one of those little key chain cards to carry with you. Periodically they send out emails with coupons in them that you can use online or in store. I usually wait for the 40% off coupons (I tend to get one of these every month or so). We are really in to board books right now because my 10-month old LOVES books--not only to read them but also to chew on them--and a 40% off coupon makes for a cheap board book.
I just got an email with their deals this weekend, and they are great. There are several different coupons you can use. My favorite is the $5 off 2 childrens books (I'm thinking maybe Mercer Mayer this time--her paperback kids books are usually only $3-4). Check out their other coupons and deals here.