**To purchase a reserved DB instance offering**

This example purchases a reserved DB instance offering.  The *reserved-db-instances-offering-id* must be a valid offering ID, as 
returned by the describe-reserved-db-instances-offering command.

    aws rds purchase-reserved-db-instances-offering \
    --reserved-db-instances-offering-id 438012d3-4a52-4cc7-b2e3-8dff72e0e706