If you are thinking of refinancing or getting a car loan then you might want to spend a few minutes with this little mortgage calculator. Just put the information (down payment, loan amount, APR, and term) in the boxes and the monthly payment will automatically update.
Also, make sure you check your credit rating before you apply for a loan.. your credit score might be affected by incorrect information from one of your previous lenders, and a low credit score will have a negative impact on the APR you qualify for.