Comment by lambdaone

I had a client with a system just like this. EBS, S3, RDS, Cognito, the lot. It cost $00s per month under almost no load, and was a maintenance nightmare - which was the real problem, not the cost, as it stopped working altogether eventually. A bit of hacking later, it all fits on a single VM that costs ~$10/month to run and is far easier to build, deploy and maintain.