EC2 Instance Purchasing Options

Allows running instances on demand.
Suitable for short workloads.
Predictable pricing, billed by the second (for Linux or Windows after the first minute) or by the hour (for other operating systems).
Highest cost but no upfront payments or long-term commitments.
Recommended for short-term, uninterrupted workloads where application behavior is unpredictable.

Offers up to 72% discount compared to On-Demand instances.
Requires reserving specific instance attributes (instance type, region, tenancy, OS).
Specify a reservation period: one year or three years for more discounts.
Payment options: upfront, partially upfront, or no upfront (all upfront provides maximum discounts).
Scope: specific region or Availability Zone (AZ) for reserved capacity.
Suitable for steady-state usage applications (e.g., databases).
Can be bought or sold in the marketplace if no longer needed.

Allows changing instance type, instance family, operating system, scope, and tenancy.
Offers up to 66% discounts (less than standard Reserved Instances due to flexibility).

Offers similar discounts as Reserved Instances (up to 72%) based on long-term usage.
Commit to a specific amount of usage in dollars per hour (e.g., $10 per hour for one to three years).
Usage beyond the Savings Plan is billed at On-Demand prices.
Locked to specific instance family and region (e.g., m5 in US East 1).
Flexible across instance sizes (e.g., m5.xlarge, m5.2xlarge).
Can switch between Linux and Windows OS.
Can switch between host, dedicated, and default tenancy.

Offers the most aggressive discounts (up to 90% compared to On-Demand).
Instances can be lost at any time if the spot price exceeds the defined maximum price.
Most cost-efficient instances.
Suitable for workloads resilient to failure:
- Batch jobs
- Data analysis
- Image processing
- Distributed workloads
- Workloads with flexible start and end times.
Not suited for critical jobs or databases.

Provides an entire physical server dedicated to your use.
Use cases:
- Compliance requirements.
- Using existing server-bound software licenses billed per socket, per core, or per VM.
Payment options:
- On-Demand (paid per second)
- Reserved (one or three years).
Most expensive option.
*Use cases when you need to access the physical server and get a dedicated host.
Use cases:
- Software licenses with bring your own license model.
- Companies with strong regulatory or compliance needs.

Instances run on hardware dedicated to you, but you may share the hardware with other instances in the same account.
No control over instance placements.
Difference from Dedicated Hosts:
- Dedicated Instances: Own instance on own hardware.
- Dedicated Hosts: Access to the physical server itself, providing visibility into lower-level hardware.

Reserve On-Demand instances in a specific AZ for any duration.
Access to the capacity whenever needed.
No time commitment; can reserve or cancel at any time.
No billing discounts - the only purpose is to reserve capacity.
To get billing discounts, combine with Regional Reserved Instances or Savings Plans.
Charged at On-Demand rates whether or not instances are running.
Suitable for short-term, uninterrupted workloads that need to be in a specific AZ.

On-Demand: Like a resort where you come and go as you please, paying the full price.
Reserved: Like planning and staying for a long time (one to three years) at a resort, getting a good discount.
Savings Plan: Committing to spending a specific amount (e.g., $300 per month) at the resort, with flexibility to change room types.
Spot Instances: Last-minute discounts on empty rooms, but you can be kicked out if someone pays more.
Dedicated Host: Booking the entire building of the resort (your own hardware).
Capacity Reservation: Booking a room, even if unsure if you'll stay, paying full price to ensure availability.

Instance: m4.large in US East 1
- On-Demand Price: $0.10
Spot Price: Up to 61% off (example).
Reserved Instances: Different pricing based on term (one or three years) and upfront payment options.
EC2 Savings Plan: Same discounts as Reserved Instances.

*Reserved convertible instances rates were also listed.

*Dedicated Host Reservation: Up to 70% off (because you reserve your host).

*Capacity Reservation: On-Demand price.