Indeed, $100 is way too low. I was quoted 260 CAD a couple of weeks ago, which is close to 200 USD (they said about $260, whatever that means). The quote was obtained at the dealership over the phone and the person on the other end could not explain what exactly is included in the price.
Yeah, my local Toyota dealer charges $299 for a fluid exchange, so the $100 service must have been d/f only.