You store a normal AMI on S3, which is $.15/GB. If you care about costs, you should be doing all of your high IO tasks on the /mnt swap drive, so your IO costs

You store a normal AMI on S3, which is $.15/GB. If you care about costs, you should be doing all of your high IO tasks on the /mnt swap drive, so your IO costs should be pretty low. It's probably a wash.