From Eric Mindek:
After inputting all of the information you'll know how much you'll expect to be paying each month. Adjusting any of these values is quick and super easy. You can even use this app while negotiating with the salesman! You no longer have to rely on the dealership for this information. You now have the power back while negotiating. Having all of this information at your finger tips will save you a lot of grief and help to keep your hard earned money in your pocket!