Amazon Aurora Serverless is a cost-effective, auto-scaling solution that can run a MySQL or PostgreSQL compatible database without requiring manual instance management, thus minimizing operational overhead. It is best suited for variable workloads and offers a pay-per-second billing. Amazon RDS does not offer the same level of automation as the serverless option. Amazon DynamoDB, while being a managed NoSQL database service, is not compatible with Oracle's SQL. Amazon Redshift is an analytics database and would likely incur higher costs due to its data warehousing nature.