I had my first oil change yesterday and the dealer put in synthetic. I didn't have to suggest it or beg for it as it appears some have had to do; they put it in because that is what is recommended for the car. However they did charge me $20 extra for it. Is that typical? Why does it cost more?

I'm anxious to see if my mileage goes up. I was averaging about 37.5 mpg; I'm in lots of stop n go traffic and I use my AC all the time (eco mode). I'm also pretty careful about maximizing fuel economy.