From Deal Dude:
Since at least 1986, the FBI has been tracking down U.S.-based terrorists who fraudulently redeem Sunday newspaper grocery coupons to fund attacks. During the trial of the men who bombed the World Trade Center in 1992, investigators claimed that U.S.-based cells had raised $100 million by processing coupons through stores they owned in New York, New Jersey and Philadelphia. According to one report, about $500 million worth of the $3.8 billion in coupons distributed each year are redeemed fraudulently. For more details, see Ben Johnson Jacobson's 1998 testimony before the U.S. Senate Judiciary Committiee on Terrorism and Technology.
In 2006 Jacobson wrote us with an update: "Coupons are still a means of financial support for terror cells operating within the U.S. This has been demonstrated over the past few years by various arrests of terrorist sympathizers within the U.S. who have used grocery coupons to finance their activities."