How do I create quotes that have both an upfront cost and a recurring fee accurately?

Our business has one-off sales, which is easy to quote and show the sale's value to the client. However, when we extend this out to include monthly recurring fees (for service or licenses), we have struggled to reflect the total sale's value accurately to the client. For instance, we sell a hardware device with three years of monthly security services. The device is billed upfront, and the monthly security services are billed on the first of each month.