Elastic Pool is a collection of databases with a shared set of resources managed via a SQL Database Server. The benefit of using an Elastic Pool in Azure SQL Server database is that using it, a single database can be moved in and out of an elastic pool, which gives us flexibility.
In the following video, I have briefly explained the role of Elastic Pools in Azure SQL Server Database. Also, you will get to understand why Elastic Pool is considered a Cost-effective solution.

Elastic Pools For Azure SQL Server Database
Jul 16 2019