Pricing for Read Replica for RDS

Hello.

Yes, read replicas cost the same as regular RDS instances.
In other words, if you use the same instance size as the writer instance, the price will be doubled by simple calculation.
https://aws.amazon.com/rds/faqs/?nc1=h_ls

A read replica is billed as a standard DB Instance and at the same rates. Just like a standard DB instance, the rate per “DB Instance hour” for a read replica is determined by the DB instance class of the read replica – please see pricing page for up-to-date pricing. You are not charged for the data transfer incurred in replicating data between your source DB instance and read replica within the same AWS Region.