Yes, that's the figure you'll get if you set the interest rate to 0 in the "Amortization period" section (and set the time period to 36 months).

By default, we assume a 10% cost-of-capital, which leads to the $706/month figure you see otherwise for cr1.8xlarge over 36 months. The difference reflects the fact that, all other things being equal, paying a lump sum up front is generally less desirable than month-to-month payments. You can adjust the interest rate parameter according to your situation.