The pricing for AWS RDS is determined by several factors, including instance type, storage size, data transfer, and the number of I/O operations. AWS offers different pricing models such as On-Demand, Reserved Instances, and Spot Instances.

• Instance Type: The cost of an RDS instance depends on the instance type (e.g., memory, vCPU) you choose for your database.
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• Storage Size: The cost of storage is based on the amount of data stored in RDS, and it varies by database engine and region.
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• Data Transfer: Data transfer pricing is based on the amount of data transferred between RDS and other AWS services or the internet.
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• I/O Operations: I/O operation pricing is based on the number of reads and writes operations performed on RDS.

AWS RDS offers three pricing models: On-Demand, Reserved Instances, and Spot Instances.

1. On-Demand: On-Demand pricing is based on hourly usage, with no upfront payment or long-term commitment. This pricing model is suitable for applications with unpredictable workloads or short-term projects.
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2. Reserved Instances: Reserved Instances (RI) provide significant discounts over On-Demand instances, with savings of up to 75% on RDS costs. RIs require an upfront payment and a long-term commitment, making them suitable for applications with steady workloads and predictable usage.
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3. Spot Instances: Spot Instances allow you to bid for unused EC2 instances, saving up to 90% on RDS costs. However, Spot Instances are suitable for non-critical workloads that can be interrupted, and they may not be available all the time.

The table below outlines an example of AWS RDS pricing based on the instance type, storage, data transfer, and I/O operations.

Note that pricing may vary based on the instance type, database engine, and region.