Effective September 1,2015, we are decreasing the price for Virtual Tape Shelf (VTS) storage by 30-36% for Gateway-Virtual Tape Library (VTL) in the US East (Northern Virginia), and US West (Oregon),Europe (Ireland) regions. Data stored in VTS is backed by Amazon Glacier, and this change reflects the storage price reduction announced by Glacier on September 16, or 2015. This unique pricing will bewitch effect automatically and no action is required on your part. For further details please visit AWS Storage Gateway Pricing page.
Source: amazon.com