We allow you to create unlimited snapshots on all of our plans, which are based on your monthly AWS spend levels.
You can then set retention periods for your 'Delete Snapshots' task where after a certain number of days, snapshots can be deleted automatically for you.
Each AWS account has limits, per region, on the number of Amazon RDS resources that can be created. Once a limit for a resource has been reached, additional calls to create that resource will fail with an exception.
For more information on default limits for Amazon RDS, click here