What is a good reasonable offer for this used 2011 Hyundai Sonata?

This Sonata is used from a Toyota dealer so it is not certified. It has 23,000 miles on it with a clean Carfax, however no serviced record found. The dealer listed priced is $20,500usd, what do you think is a good out of the door price including taxes and everything for this vehicle? Thank you.