I would offer a little lower than 18k and see if they take it. It is kinda hard to sell them in certain areas right now because of gas prices. The price of 18k is a slight bit on the high side, tell him to offer 16k and see what they say. 18k is still not a bad price though. There are a ton of guys who have over 100k miles. Check out www.nhtoc.com and ask around.