Amazon Aurora is a scalable database service on AWS that simplifies the process of creating and managing a MySQL or Postgres-compatible database. However, its pricing structure is not as straightforward as one might believe. Factors to consider when estimating costs include instance type, replicas, storage configuration, data transfer costs, cross-region replication, connection pooling, change management, backups, and monitoring. PlanetScale offers a more simplified and managed approach with its pricing model, including some features at no additional cost.