So, I eat subway probably 4x per week, during the workdays. On Monday/Wednesday I buy a 12" ham on jalapeno/cheddar bread with spinach, tomatoes, green bell peppers, & olives. That 12" lasts me for 2 days (6" half per day). With each receipt I get, there is information on how to get a free cookie. Also on the receipt is the store ID, the date and time I bought my meal.
In order to get the free cookie, you have to go to a website (www DOT tellsubway DOT com) and answer some marketing information. You then enter in the code they give you on your receipt and return with the receipt+code and receive your free cookie.
Rather than going to the website, you can also enter your own code in the following format:
10-XXXXX-0-YYYY-ZZZZ,
where XXXXX = store ID;
YYYY = MMDD of the date of your visit; and
ZZZZ = HHMM of the hour/minute of your visit.
For example, if you go to store ID 12345, at noon on July 4th, your free cookie code would be:
10-12345-0-0704-1200
Now I assume the time is 24-hour clock, but other than that, it pretty much works. There's no checking of your code to see if its valid, but there's no reason for the cashier to think otherwise.
Enjoy!