Amazon SimpleDB - Wikipedia
"Amazon SimpleDB is a distributed database written in Erlang by Amazon.com. It is used as a web service in concert with Amazon Elastic Compute Cloud (EC2) and Amazon S3 and is part of Amazon Web Services. It was announced on December 13, 2007.
...Free Tier for 1 GB of data & 25 machine hours.
Transfer to other Amazon Web Services is free of charge"