AWS on a Budget: Smart Cost Planning for the Cloud

Gladys wairimu
Apr 15, 2025
4 min read

Cloud costs can spiral quickly if you're not intentional. AWS offers powerful tools to stay on top of your budget, but many teams don’t use them early enough. In this article, I share how I modeled a fictional client's AWS architecture using AWS Pricing Calculator, and how services like AWS Budgets, Spot Instances, and Savings Plans can help optimize cloud spend.

🤑Spoiler: 2 of those methods are completely free to use.

Client Problem Summary

My client is planning to move her surf shop’s webstore to the cloud but is concerned about cost efficiency. Her current traffic patterns show high daytime usage and significantly lower activity at night, suggesting potential for scaling down infrastructure during off-peak hours. She’s unsure how to start estimating AWS costs and is questioning whether to replicate her on-premises setup or right-size their resources for the cloud. She also needs guidance on choosing the right AWS services that align with her current hardware and on handling unexpected spikes in resource demand.

The Lab Project: Model Your Use Case Using AWS Pricing Calculator To Estimate Costs

Want to know an estimate of how much your AWS cloud infrastructure will cost before migrating to the cloud or purchasing any AWS resources? AWS Pricing Calculator is a great tool for that. Oh, and it’s completely free to use. In this part, I’ll show you how it works using a practical example.

Step 1– Create a Pricing Logical Group

A logical pricing group is a way to categorize your cost estimates based on various technical and business perspectives. When using Pricing Calculator, it’s best to create logical pricing groups as this helps to neatly and clearly group related services together. Additionally, one can create a cost estimate for each logical pricing group individually helping you to understand the cost implications of individual infrastructures or departments. For example, you can create groups based on a cost center (a team or department that incurs cost but doesn’t directly generate revenue), services to buy on AWS such as S3, architectural tiers such as database tier and storage tier, and so on.

Using the example of my client, to create a logical group, click the ‘’Create group’’ option on the pricing calculator as shown below.

Step 2–Add Services to Logical Groups

Once that’s done, add AWS services you wish to use in the logical pricing group you have created using the ‘’Add service’’ button. In my example, I added an EC2 instance for my client in my pricing group. Additionally, I customized the instance by specifying key configurations such as tenancy, instance type, region, workload, Elastic Block Store (EBS) volume, network performance and operating system.

Step 3– Choose a Pricing Model

AWS offers various pricing models to help customers optimize their costs and capacity needs. I explored the different EC2 pricing models available which included On-Demand Instances, Savings Plans, Reserved Instances, Spot Instances, and Convertible Reserved Instances. The calculator automatically updates the estimated cost as you toggle between these options, making it an excellent tool for experimenting and comparing pricing strategies based on your workload needs.

Step 4– Share Your Cost Estimate

Finally, once you've added your services to logical pricing groups and configured your resources to reflect your specific requirements, you can easily share the cost estimates in multiple formats — including CSV, PDF, JSON or a shareable link. Here is the cost estimate from this lab project: https://calculator.aws/#/estimate?id=14e995e147507b49d29083ee24399baa2dd07a00.

How this helps

Using the AWS Pricing Calculator gave my client a clear, upfront view of what their cloud setup could cost based on her unique traffic patterns and needs. It allowed us to model a dynamic architecture—scaling down resources at night to save on costs—and explore different instance types that matched or improved upon her current hardware. This helped her see the financial impact of right-sizing instead of simply replicating her on-prem setup. Most importantly, it gave her the confidence to plan her company’s migration with cost transparency and flexibility in mind.

🤔 The AWS Pricing Calculator provides valuable cost estimates, but it's important to understand its underlying assumptions. Actual costs may vary depending on factors not included in the calculations. For details on these potential variations, please refer to the AWS Calculator Assumptions page: https://aws.amazon.com/calculator/calculator-assumptions/.

Moving Beyond Estimates: Real-Time Cost Management

AWS Budgets lets you set custom cost and usage limits, so you can get alerts before you overspend—not after. You can track actual spend against your forecast and get notified via email or SNS when thresholds are crossed. It’s great for teams that want more control and visibility without constantly checking the billing dashboard. It helps enforce financial accountability across projects, especially in multi-team environments.

Choosing the Right Compute Pricing Models

Here are the pricing models available for EC2 instances, when best to use them and their cost implications:

On-Demand Instances – Flexible, but priciest for long-term use. Suitable for short term and unpredictable workloads.
Reserved Instances – Great for predictable long-running workloads, and has up to 75% savings.
Savings Plans – A flexible alternative to RIs. Instead of committing to a specific instance, you commit to a dollar amount per hour over 1 or 3 years. It covers EC2, Lambda, and Fargate usage with significant savings.
Spot Instances – Ideal for fault-tolerant, stateless workloads like batch jobs and big data analysis. Offers massive discounts (up to 90%) for spare AWS capacity through bids.
Convertible Instances – Great if your needs might change. You can exchange them for different instance types with equal or greater value. Offer more flexibility than standard reserved instances.

🧠 Pro Tip: Most cost-effective architectures use a combination of these models, for example, reserved or savings plans for baseline needs, and spot for scaling.

✅ In Conclusion…

Cost efficiency on AWS starts with understanding your needs and planning ahead. Tools like AWS Pricing Calculator and AWS Budgets can give you visibility and control before and after deployment—without costing you a dime. By modeling your architecture, exploring the right pricing models, and taking advantage of flexible options like Spot and Savings Plans, you can build a cloud environment that scales smart and saves money.