The correct tool is Cost Explorer, as it provides detailed graphical reports for analyzing cloud spending and usage patterns over time, helping users to understand their cloud costs and optimize their budget. Budgets allows users to set custom budget thresholds to monitor costs and usage patterns but does not provide the same in-depth graphical analysis. The Pricing Calculator is used primarily to estimate the costs for specific services before deployment and does not track actual expenditure or usage. Billing Conductor is not a real service offered for cost management or analysis.