Have you been to www.oldnavyweekly.com yet? Old Navy puts coupons good for one week only on this site. You search throughout the webpage flyer with your cursor looking for hidden coupons and offers. There are only a certain number of these so once they are gone, they're gone. Some of the coupons are as good as $60 off $100 and so on.
I usually can find a 15 or 20% off coupon but have never struck it rich with the big ones. It may be because I just found out recently that Old Navy changes their coupons at about 3 a.m. Friday mornings, and that several people have been staying up until then just to grab these deals. Old Navy has caught on to this and is now beginning to release the bigger coupons throughout the week. Deal Seeking Mom in my faves section below outlines where these coupons are located on the site.