August 2012 - While in the line at the grocery store and eyeing the Batman movie toy display stocked in between two registers, I spotted a pad of paper sitting on the top of the display... I darted over, grabbed the top sheet, and got back in my own line.
The pad was a batch of order forms for a "FREE Batman Duffle Bag! with $15 purchase of Batman product by Mattel." In the fine print, it mentions that if you buy $15 or more of Mattel Batman toys from "this retailer" and send in $5 for shipping, they will send you a free duffle bag.
You can also order online at: http://service.mattel.com/promotion?id=Batman
The online order page specifies that your purchase can be from any retailer EXCEPT Kmart, Walmart, Toys'R'Us, or Target. You'll need your UPC codes from the packaging and your original receipts dated through August 31st.