As the seller, I might respond by saying, "Well, I believe that the car is worth $12,000 based on its condition and recent maintenance. However, I'm open to negotiation. What would be your offer?"
At this point, you could consider making an initial offer that is lower than the asking price, but not so low that it offends me or makes me unwilling to negotiate further. For example, you could say, "Based on my research and the current market value for a car with similar mileage and condition, I would like to offer $10,000. How do you feel about that?"
By making an initial offer, you show that you are interested in negotiating and that you have done your research, which can help establish your credibility as a buyer. However, it's also important to be flexible and open to further negotiation. Remember to actively listen to my response and be prepared to adjust your offer accordingly.