Take into account various offering types

[ckelner]

See http://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/EC2.html#describeReservedInstances-property

And:

{
  "ReservedInstancesId": "d16f7a91-77a2-4103-a220-d03f14851ef2",
  "InstanceType": "c3.large",
  "AvailabilityZone": "us-east-1d",
  "Start": "2014-09-01T00:00:00.000Z",
  "End": "2017-08-30T23:59:59.000Z",
  "Duration": 94608000,
  "UsagePrice": 0,
  "FixedPrice": 482.6,
  "InstanceCount": 6,
  "ProductDescription": "Linux\/UNIX (Amazon VPC)",
  "State": "active",
  "Tags": [

  ],
  "InstanceTenancy": "default",
  "CurrencyCode": "USD",
  "OfferingType": "Heavy Utilization",
  "RecurringCharges": [
    {
      "Frequency": "Hourly",
      "Amount": 0.0209
    }
  ]
}