Amazon recently announced new options for their EC2 reserved instances.
http://aws.amazon.com/ec2/reserved-instances/?ref_=pe_8050_22086710
With this product you pay a small amount up-front for a reserved instance and in exchange Amazon will lower your hourly rate. The more you pay the lower the hourly rate.
Keyapt SMS have a server that runs continuously. Therefore we should look a purchasing an heavy utilisation instance. This will save 41% on a one year term. Unfortunately the benefit does not extend to the cost of the load balancer in our Elastic Beanstalk set up.