Defined in github.com/aws/aws-sdk-go/service/ec2/api.go
Purchases a Reserved Instance for use with your account. With Reserved Instances, you obtain a capacity reservation for a certain instance configuration over a specified period of time and pay a lower hourly rate compared to On-Demand instance pricing.
Use DescribeReservedInstancesOfferings to get a list of Reserved Instance offerings that match your specifications. After you've purchased a Reserved Instance, you can check for your new Reserved Instance with DescribeReservedInstances.
For more information, see Reserved Instances (http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/concepts-on-demand-reserved-instances.html) and Reserved Instance Marketplace (http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ri-market-general.html) in the Amazon Elastic Compute Cloud User Guide.