Cloud computing/Amazon Web Services/Relational Database Service (RDS)
Amazon Relational Database Service (or Amazon RDS) is a distributed relational database service by Amazon Web Services (AWS), also included in the AWS Free Tier option.
You can create different types of DBs using AWS web page or AWS CLI.
Regarding possible cost while learning AWS RDS, just be aware that you will be able to stop AWS RDS instances from AWS Management Console or AWS CLI for 7 days period at a time, but after those 7 days, it will be automatically started by AWS. 
Basic AWS Cli Commands
Describe some basic parameters of RDS instances:
aws rds describe-db-instances --output text --query 'DBInstances[*].[DBInstanceArn,Engine,DBInstanceIdentifier,DBInstanceStatus]' arn:aws:rds:eu-central-1:4523523466:db:my_branches_name postgres my_branches_name available
Describe additional parameters of RDS instances:
/usr/bin/aws rds describe-db-instances --output text --query 'DBInstances[*].[DBInstanceArn,Engine,EngineVersion,AvailabilityZone,MultiAZ,DBInstanceIdentifier,DBInstanceClass,AllocatedStorage,DBInstanceStatus,PubliclyAccessible,MasterUsername]' arn:aws:rds:eu-central-1:4523523466:db:my_branches_name1 postgres 9.6.6 eu-central-1b True my_branches_name1 db.t2.micro 50 available False root arn:aws:rds:eu-central-1:4523523466:db:my_branches_name1 postgres 9.6.6 eu-central-1a False my_branches_name2 db.t2.medium 20 available False root
- What is the maximum Database storage size?
- Can i limit the size of my Database?
- Do i have to stop my database to increase storage?
- Wikipedia: Amazon Relational Database Service