Spot Instances allow customers to purchase unused Amazon EC2 compute capacity at discounted prices, which can be interrupted by AWS with a two-minute notification if AWS needs the capacity back. This makes them an excellent choice for workloads that are flexible and can withstand interruptions, such as batch processing jobs. On-Demand Instances provide the most flexibility without upfront payment or long-term commitment but are more costly compared to Spot Instances. Reserved Instances provide a discounted hourly rate and an optional capacity reservation in exchange for a contract term, but they do not handle interruptions and are less suitable for unpredictable workloads. Savings Plans offer lower prices in exchange for a commitment to a consistent amount of usage (in USD/hour) over a 1 or 3-year period and would not provide the cost savings for interruptible workloads as Spot Instances would.