With Aurora (PostgreSQL and MySQL), when you add a read replica instance to an existing cluster, you are billed for the instance hours based on the instance type you choose for the replica instance. You are NOT billed for additional storage - there is no additional storage for read replica instances in Aurora, as the read replica instances share access to the same Aurora storage volume as the primary read-write instance; as such, data is not replicated to the replica instances.
Thanks for being an Aurora PostgreSQL customer!
-Kevin J, PM for Aurora PostgreSQL
Need information regarding Aurora AZ FailureAccepted Answerasked 5 months ago
Aurora Replica Sizing vs. Source DB Sizing - Do they need to match?Accepted Answerasked 4 years ago
Instance size of a read replica in secondary region of Aurora PostgreSQL Global DatabaseAccepted Answerasked a month ago
Elastic Search pricing: Pay as you go or not?asked a year ago
How to ensure replica is in sync between AWS RDS PSQL primary DB and Aurora RDS PSQL replica cluster?asked 6 months ago
Aurora read replica for RDS Postgres and long-term useasked 2 months ago
RDS Postgresql migrate to Aurora Postgresql. Not showing "Aurora read replica" & "Migrate snapshot" options.Accepted Answerasked a year ago
Aurora PostgreSQL Replica Pricingasked 3 years ago
"Create Aurora Read Replica" option not available to migrate from RDS Postgres 11.12 to Aurora 11.12.asked 8 months ago
will RDS auto create a new instance whenever the primary instance failover in Aurora Cluster?asked 3 months ago