# AWS Cost Inspection

> Check AWS spend, cost, budget status, or "how much am I spending" using the FREE Budgets/CloudWatch APIs — never the paid Cost Explorer API. Use whenever a task involves inspecting AWS costs, budgets, month-to-date spend, forecasts, budget-action status, or verifying whether a budget/tripwire has been crossed. Cost Explorer (aws ce ..., ce:GetCostAndUsage) and the console cost widgets bill $0.01 per request — repeatedly querying them to "quickly check" a small budget can itself trip that budget.

- Skill: `aws-sbg-at-the-university-of-kentucky/aws-cost-inspection` (Agent Skill)
- Install (CLI): `npx skillmds@latest add aws-sbg-at-the-university-of-kentucky/aws-cost-inspection`
- Raw SKILL.md: https://api.skillmd.com/api/skills/aws-sbg-at-the-university-of-kentucky/aws-cost-inspection/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: DevOps & Infra
- Author: AWS-SBG-at-the-University-of-Kentucky (https://skillmd.com/u/aws-sbg-at-the-university-of-kentucky)
- Updated: 2026-09-22
- Page: https://skillmd.com/skills/aws-sbg-at-the-university-of-kentucky/aws-cost-inspection

---


# Inspecting AWS cost & budget state — cheaply

## The rule

**Do NOT use Cost Explorer to routinely check spend.** The Cost Explorer API
is billed **$0.01 per request**, and so is every `aws ce ...` call and every
console "Cost and usage" / Cost Explorer widget load. On a tiny budget (e.g. a
`$0.01` tripwire), the act of checking can be what trips it. Reach for the free
sources below first; use Cost Explorer only when itemized cost breakdowns are
genuinely required, deliberately, and tell the user it costs ~$0.01/request.

## Free ways to inspect cost/budget (prefer these)

### 1. AWS Budgets API — free, and it's the number budget actions evaluate
```bash
# Recorded spend + forecast for one budget (ActualSpend is what actions check):
aws budgets describe-budget --account-id <ACCOUNT_ID> --budget-name <NAME> \
  --query 'Budget.{limit:BudgetLimit.Amount,actual:CalculatedSpend.ActualSpend.Amount,forecast:CalculatedSpend.ForecastedSpend.Amount,updated:LastUpdatedTime}'

# All budgets in the account:
aws budgets describe-budgets --account-id <ACCOUNT_ID> \
  --query 'Budgets[].{name:BudgetName,limit:BudgetLimit.Amount,actual:CalculatedSpend.ActualSpend.Amount}'

# Budget-action status / history (STANDBY | PENDING | EXECUTION_SUCCESS | ...):
aws budgets describe-budget-action --account-id <ACCOUNT_ID> --budget-name <NAME> --action-id <ID>
aws budgets describe-budget-actions-for-account --account-id <ACCOUNT_ID>
aws budgets describe-budget-action-histories --account-id <ACCOUNT_ID> --budget-name <NAME> --action-id <ID>
```
Note: `CalculatedSpend` lags — Budgets refreshes ~2–3×/day (8–12h apart), so it
can read $0.00 while the Bills page already shows a charge. That lag is normal.

### 2. CloudWatch billing metric — free (needs billing alerts enabled, us-east-1)
```bash
aws cloudwatch get-metric-statistics --namespace AWS/Billing \
  --metric-name EstimatedCharges --dimensions Name=Currency,Value=USD \
  --start-time <ISO> --end-time <ISO> --period 21600 --statistics Maximum \
  --region us-east-1
```

### 3. Free Tier usage — free
```bash
aws freetier get-free-tier-usage --region us-east-1   # usage toward free-tier limits
```

### 4. Audit who queried costs (e.g. find who ran up Cost Explorer charges) — free
```bash
aws cloudtrail lookup-events \
  --lookup-attributes AttributeKey=EventName,AttributeValue=GetCostAndUsage \
  --start-time <ISO> --end-time <ISO> --region us-east-1
```
The `userAgent` distinguishes `aws-cli`/SDK calls (billed) from console/browser
(`Mozilla/...`) calls.

## The paid Cost Explorer calls to avoid for routine checks
`aws ce get-cost-and-usage`, `get-cost-and-usage-with-resources`,
`get-cost-forecast`, `get-dimension-values`, `get-cost-categories`, etc. — each
~$0.01/request — and the Cost Explorer / "Cost and usage" console widgets.

When an itemized per-service or per-day breakdown is genuinely needed, Cost
Explorer is the only source: do it in ONE deliberate paginated call and say it
costs ~$0.01. Don't loop it or use it to poll.

## Watching a budget/tripwire over time
Poll `aws budgets describe-budget` (free) — never Cost Explorer. Tell the user
the recorded spend lags real usage by 8–12h, so status changes appear on
Budgets' refresh cadence, not immediately.