Borrower promises to make a single, final payment for the entire balance owed to the Payee on or before. Here's the information you'll need to have handy to complete your unsecured promissory note, interest-only with balloon final payment.Here's the information you'll need to have handy to complete your secured promissory note, interest-only with balloon final payment. A monthly interest rate can be included on the promissory note. Interest Only Payments. Edit, sign, and share interest only loan agreement template online. No need to install software, just go to DocHub, and sign up instantly and for free.