Billing and Pricing
Billing and Pricing tests how AWS charges for usage, how to reduce cost with the right purchasing option, and which tools and support plans exist. Expect scenario questions about steady versus variable workloads and about consolidated billing.
Purchasing options
On-Demand has no commitment and the highest unit price. Reserved Instances commit to one or three years for a discount and are suited to steady-state workloads. Savings Plans commit to a spend per hour for one or three years in exchange for lower rates. Spot Instances use spare capacity at up to a 90% discount but can be interrupted, so they suit fault-tolerant, stateless, or batch work. Data transfer, storage requests, and provisioned capacity are billed separately from compute.
Free Tier and organizations
The AWS Free Tier includes always-free allowances, 12-month offers, and short-term trials. AWS Organizations with consolidated billing combines accounts into one bill, aggregates usage for volume discounts, and can share Reserved Instance and Savings Plan benefits. Cost allocation tags make spend attributable to projects or teams.
Tools and support
AWS Cost Explorer visualizes and forecasts spend; AWS Budgets alerts or acts when thresholds are crossed; the Cost and Usage Report provides the most detailed line-item data; the AWS Pricing Calculator estimates a planned architecture. Support plans are Basic, Developer, Business, Enterprise On-Ramp, and Enterprise; faster response and a technical account manager come at higher tiers.
Worked example
A company runs a 24/7 production database with predictable load, plus a nightly image-rendering batch that can restart. Choose Reserved Instances or a Savings Plan for the database because usage is steady and long-lived; choose Spot for the batch because interruption is tolerable and the discount is largest. Reasoning: matching commitment to predictability lowers cost without harming availability.
Traps
Spot is a poor fit for stateful databases. Reserved Instances do not make data transfer free. Consolidated billing does not remove the need to tag resources. The TCO focus is comparing on-premises and cloud costs, not a monthly bill viewer.