When we did this, the site told us we could expect about $13,200 for the 2015 Audi A4 as a trade-in. When a KPRC 2 employee drove his car over, he checked in and waited about 45 minutes before a Carmax employee offered him $13,000. Take it to a DealershipArmed with the information you have already gathered, you can now take your trade-in to a dealership where you plan to purchase your vehicle. When they tell you how much they will give you for your trade-in, you will already know if you can do better. In this scenario, you can likely make the most money, but there are a few more hassles.