Fetch **authoritative, live Azure prices** — VM/disk/IP hourly rates, Spot, Reserved Instance, and Savings Plan — directly from the **Azure Retail Prices API**. This is the **mandatory source of truth** for every numeric price the cost specialist quotes. Never state a hard-coded, cached, or model-recalled rate: always fetch, then cite the exact `$filter`, `armRegionName`, `armSkuName`, `currencyCode`, `retailPrice`/`unitPrice`, `effectiveStartDate`, and a retrieval timestamp.
