First Oil Change Free for everyone?

I brought my 5 in for an oil change today. I bought the car in March with 823 miles already on it. The car had been shuffled between dealers. As of today it has a whole 4555 miles on it (about 600 miles a month). Six months is the limit in my head for oil. Most of my trips are 9 miles of highway followed by days of sitting (I work in the travel industry).

Anyways I brought my car to a dealer that I did not buy my car from prepared to pay 24.95....but it was free. Is this a Mazda thing or a local dealer thing?
 
Back