ElastiCache Reserved Nodes
Reserved cache nodes let you make a one-time up-front payment for a cache node and reserve the cache node for a one- or three-year term at significantly lower hourly rates.
For the t2, m3, and r3 families, reserved cache nodes are available as Heavy Utilization offerings. Reserved cache nodes for older node types are available in three varieties—Heavy Utilization, Medium Utilization, and Light Utilization—that enable you to optimize your ElastiCache costs based on your expected utilization.
You can use the command line tools, the API, or the AWS Management Console to list and purchase available reserved cache node offerings. The three types of reserved cache node offerings are based on class and duration.
For more information on reserved nodes, go to Amazon ElastiCache Reserved Cache Nodes.