As an organization grows, it doesn't stop at a single account. Splitting accounts by team, by environment, and by project is common. That makes billing and governance complex. Today we'll organize AWS Organizations and consolidated billing for grouping, managing, and paying across many accounts, the Pricing Calculator for calculating costs before moving to the cloud, and the TCO concept for comparing total cost of ownership against on-premises.
There are two core questions: "How do I govern the costs and permissions of many accounts from one place?" and "How do I gauge costs before using them?"