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Introduction
AWS offers multiple pricing models, and choosing the right one can mean the difference between an optimized cloud bill and a painfully inflated one. Many organizations simply default to On-Demand pricing out of habit or lack of awareness, leaving significant money on the table. This blog demystifies AWS pricing models and helps you make smarter purchasing decisions.
On-Demand Pricing: The Default but Not Always the Best
On-Demand pricing lets you pay for compute capacity by the hour or second with no long-term commitments. This flexibility comes at a premium — On-Demand is the most expensive pricing model for EC2.
On-Demand makes sense for unpredictable workloads, spiky traffic patterns, or short-term experiments. For steady-state workloads, it is almost always more cost-effective to use a commitment-based model.
Savings Plans: Flexible Commitments with Significant Discounts
Savings Plans offer discounts of up to 66% off On-Demand pricing in exchange for a commitment to spend a specific amount per hour over one or three years. There are two types:
Compute Savings Plans: Apply to any EC2 instance regardless of family, size, region, or OS. Also apply to Lambda and Fargate. Maximum flexibility.
EC2 Instance Savings Plans: Apply to a specific instance family in a specific region. Offer higher discounts (up to 72%) in exchange for less flexibility.
Reserved Instances: Deep Discounts for Predictable Workloads
Reserved Instances provide discounts of up to 72% compared to On-Demand for specific EC2 instance types. They come in three payment options:
No Upfront: Pay monthly with a moderate discount.Partial Upfront: Pay some upfront for a larger discount.All Upfront: Pay the entire term upfront for the maximum discount.
Convertible Reserved Instances allow you to change instance families, sizes, and operating systems during the term, providing more flexibility than Standard Reserved Instances.
Spot Instances: Up to 90% Discount for Fault-Tolerant Workloads
Spot Instances use spare EC2 capacity at discounts of up to 90% compared to On-Demand prices. The catch: AWS can reclaim Spot Instances with two minutes of warning when that capacity is needed elsewhere.
Spot Instances are ideal for batch processing, big data analytics, machine learning training, and stateless web tier components that can tolerate interruption. Use Spot Instance diversification — requesting multiple instance types across multiple AZs — to minimize interruption impact.
Ozy Solutions helps clients identify appropriate workloads for Spot Instances as part of our AWS cost optimization services.
Building a Smart Purchasing Strategy
The most cost-effective approach combines multiple pricing models: commit to Savings Plans for your baseline compute needs, use On-Demand for variable demand above your baseline, and incorporate Spot Instances for fault-tolerant workloads.
Regularly review your coverage rates in AWS Cost Explorer. The Savings Plans and Reserved Instance recommendations in Cost Explorer are based on your actual usage and provide excellent guidance for optimization decisions.
For more detailed purchasing strategy guidance, visit our blog.
Conclusion
Understanding and optimizing your AWS pricing strategy is one of the highest-ROI activities available to cloud teams. Ozy Solutions‘ AWS cost optimization experts can analyze your spending patterns and develop a purchasing strategy that significantly reduces your costs without compromising flexibility.
