With Amazon EBS, you only pay for what you use. The pricing for Amazon EBS volumes is listed below.
EBS General Purpose (SSD) Volumes
Volume storage for General Purpose (SSD) volumes is charged by the amount you provision in GB per month, until you release the storage. I/O is included in the price of General Purpose (SSD) volumes, so you pay only for each GB of storage you provision.
EBS Provisioned IOPS (SSD) Volumes
Volume storage for EBS Provisioned IOPS (SSD) volumes is charged by the amount you provision in GB per month, until you release the storage. With Provisioned IOPS (SSD) volumes, you are also charged by the amount you provision in IOPS (input/output operations per second) multiplied by the percentage of days you provision for the month. For example, if you provision a volume with 1000 IOPS, and keep this volume for 15 days in a 30 day month, then in a Region that charges $0.10 per provisioned IOPS-month, you would be charged $50 for the IOPS that you provision ($0.10 per provisioned IOPS-month * 1000 IOPS provisioned * 15 days/30). You will be charged for the IOPS provisioned on a EBS Provisioned IOPS (SSD) volume even when the volume is detached from an instance.
EBS Magnetic Volumes
Volume storage for EBS Magnetic volumes is charged by the amount you provision in GB per month, until you release the storage. Volume I/O for EBS Magnetic volumes is charged by the number of requests you make to your volume. Programs like IOSTAT can be used to measure the exact I/O usage of your system at any time. However, applications and operating systems often cache at different levels, so you may see a different number of I/O requests on your bill than is seen by your application.
Snapshot storage is based on the amount of space your data consumes in Amazon S3. Because data is compressed before being saved to Amazon S3, and Amazon EBS does not save empty blocks, it is likely that the snapshot size will be considerably less than your volume size. For the first snapshot of a volume, Amazon EBS saves a full copy of your data to Amazon S3. For each incremental snapshot, only the changed part of your Amazon EBS volume is saved.
Copying EBS snapshots is charged for the data transferred across regions. After the snapshot is copied, standard EBS snapshot charges apply for storage in the destination region.
*on this page GB = 1024^3 bytes