If you've ever seen a coupon printed from a Web site and wondered if it was legit, here's a little trick. Most of the major coupon printing Web sites use special coding for each coupon that is printed. It's a bunch of numbers and is called the Veri-Fi code (most coupons also have a little Veri-Fi logo on the right hand side). You can go to this Web site and enter the code from a coupon and find out if it's real. If it is, the site verifies it as authentic and even tells you what the text on the coupon should read. Pretty cool!
In general, remember that coupons for totally FREE items or really high-value coupons (like say $6 off a bottle of Tide) are probably fraudulent, and many stores now refuse to take any Internet coupons for FREEs. (BOGOs are still OK in most cases, check your store's coupon policy.)
