Using reserved instances is not the most cost-effective way. https://aws.amazon.com/blogs/aws/new-scheduled-reserved-instances/ " Scheduled ReservedInstance model allows you to reserve instances for predefined blocks of time on a recurring basis fora one-year term, with prices that are generally 5 to 10% lower than the equivalent On-Demandrates." You can get spot instances with much lower prices: https://aws.amazon.com/ec2/spot/pricing/ "Spot instances are also available to run for a predefined duration in hourly increments up to sixhours in length at a significant discount (30-45%) compared to On-Demand pricing plus anadditional 5% during off-peak times for a total of up to 50% savings."