The pricing for Azure SQL Data Warehouse (SQL DW) consists of a compute charge and a storage charge.  For compute, it is not based on hardware configuration but rather by data warehouse units (DWU).  DWU can be scaled up or down via a sliding bar in just a couple of minutes with no down time.  You pay for DWU blocks, based on up time (you can pause your SQL DW database and not have to pay for compute while paused).

You must pay for storage, even when paused, but there is no limit to the amount of data you can put into storage.

Below is some examples of the compute pricing based in the East US region.  The pricing comes from the Azure pricing calculator:

SQL Data Warehouse, 100 DWU, $1,125/month
SQL Data Warehouse, 500 DWU, $5,625/month
SQL Data Warehouse, 1000 DWU, $11,250/month
SQL Data Warehouse, 1500 DWU, $16,875/month
SQL Data Warehouse, 2000 DWU, $22,500/month
SQL Data Warehouse, 3000 DWU, $33,750/month
SQL Data Warehouse, 6000 DWU, $67,500/month

Data warehouses will use Premium Disk storage (P30).  Below is some examples of the storage pricing based in the East US region:

SQL Data Warehouse, RA-GRS Page Blob, 1TB = $135/month
SQL Data Warehouse, RA-GRS Page Blob, 10TB = $1,351/month
SQL Data Warehouse, RA-GRS Page Blob, 100TB = $13,517/month
SQL Data Warehouse, RA-GRS Page Blob, 1PB = $135,170/month

Storage transactions are not billed; customers only pay for data stored, not storage transactions.  Inbound data transfers are free.  Outbound data transfers are charged at regular data transfer rates.  Note you could store lesser-accessed data in Azure Blob Storage and access it via PolyBase to save storage costs.

More info:

SQL Data Warehouse Pricing

Understanding Windows Azure Storage Billing – Bandwidth, Transactions, and Capacity

Understand your bill for Microsoft Azure