Bought a Groupon for two oil changes and tire rotation. I didn't care about my first car as it's a winter beater and the tires were already ok.
Before I took my second car in the next day, I took a look at my oil filter to see if they would change it. Surprisingly they didn't. Same filter which I marked. I don't even know if they changed the oil or put in quality oil as stated on the Groupon. I wouldn't trust them.