MINI Cooper S wanted, what is a reasonable price?

Hello together, I am just in the search phase for the purchase of my new car, fluctuating between a 118d and a MINI Cooper S… the question about the “what should I buy” I prefer not to ask here, because this is a very subjective decision. At the moment, however, the MINI has the nose ahead, but I ask myself “what to buy”. I live in the Munich area and am ready to spend max. 18,000 euros, would like to buy from the dealer. As equipment I had Chi li presented, otherwise so the usual… I was amazed about the price: With my budget then a car goes from mid-2007… I somehow thought that I would get away a little cheaper. Do you have tips where you can look well? On the MINI page directly seems to me to be the best, next to it mobile. en. How does it look with service intervals, so you can buy a MINI with say 60,000 km on it without hesitation? The dealer has to give a guarantee. Thanks & Best regards