A gaming company needs EC2 instances running continuously for one year with predictable, steady traffic and no interruptions. Which EC2 purchasing option provides the most cost savings while ensuring availability?

Reserved Instances (RIs) are the most cost-effective option for applications with predictable, steady usage for a one-year term, like the gaming company's scenario. RIs offer significant discounts (up to 75%) compared to On-Demand pricing in exchange for committing to a specific instance type and region for a 1-year or 3-year term. This commitment ensures availability and cost savings. On-Demand Instances are more expensive as they offer no commitment, suitable for short-term, irregular workloads. Spot Instances are the cheapest but are interruptible, making them unsuitable for continuous, uninterrupted operations. Spot Fleet combines Spot Instances and On-Demand Instances but still primarily relies on interruptible Spot capacity, which doesn't guarantee continuous availability for a critical, steady workload.