Old Navy has random secret saving codes posted on their site!
Try to enter the code:
ONSECRET20 for 20% off any Old Navy Purchase
ONSECRET30 for 30% off any Old Navy Purchase
“Offer valid to select customers on Old Navy merchandise purchased online from 5/15/2011 at 12:01 AM ET through 5/18/2011 at 11:59 PM ET. Not valid at Old Navy stores or international purchases. Promotion not valid on Old Navy Everyday Steals, Jeans, Swim, Toddler, and Baby merchandise. Qualifying amount applies to merchandise only, not value of gift cards purchased, packaging, applicable taxes or shipping & handling charges. No adjustments on previous purchases. Not valid for cash or cash equivalent. Cannot be combined with other offers or discounts, including Gap Inc. employee discount. Gap Inc. is not responsible for lost or stolen coupons.”