What began as a small coupon promotion on Facebook has turned into a marketing fiasco, according to a report by the Seattle Times.

It started on Aug. 15 when the social networking site offered coupons for 12 products.

But the Times said hackers copied and altered the legitimate coupons, which were originally for 50 cents off in many cases.

Within days, shoppers were printing millions of bogus coupons that promised free products such as shampoo and crackers.

The bottom line is to be wary of e-mails offering coupons for free products because they may be phony.