This coupon came from this contest(which I won on the first try): http://www.subwayfreshbuzz.com/getsmart/ They pulled these coupons off of their site, but I put them all into a pdf that you can download here: https://www.freestufftimes.com/wp-content/uploads/2008/06/subwaycoupons.pdf
-ADDED-you can also get a free $5 subway GC if you test ride a vespa scooter:
http://www.vespausa.com/SubwayGetSmart/