# Free sample → outline 0.01 → brief 0.02

## Single ladder · free → **0.01** outline → **0.02** brief (Base USDC)
- **Step 1 (free):** this page (3-bullet teaser) · or MCP free tools at `https://x402.devvizion.com/mcp`
- **Machine JSON (agents):** `https://x402.devvizion.com/v0/sample-outline.json?topic=x402` · or `?format=json`
- **Step 2 (first pay):** `POST /v0/outline` · **0.01 USDC** · network `eip155:8453` · payTo `0xE79e7fa7Ce7259C46F9B127b837d2907Bb036F95`
- **Step 3 (upgrade):** `POST /v0/brief` · **0.02 USDC** · same payTo (full markdown brief)
- **Why buy:** free teaser is only 3 bullets. Outline = full bullet set + lens; brief = cited research markdown.

```bash
curl -sS -X POST https://x402.devvizion.com/v0/outline \
  -H "Content-Type: application/json" \
  -d "{\"topic\":\"x402\"}"
# unpaid → HTTP 402 · settle 0.01 USDC · retry X-PAYMENT
curl -sS -X POST https://x402.devvizion.com/v0/brief \
  -H "Content-Type: application/json" \
  -d "{\"topic\":\"x402\"}"
# unpaid → 402 · settle 0.02 USDC · retry X-PAYMENT
```

## Free teaser — 3 of 4 bullets

_topic `x402` · lens payments · 2026-07-26T04:00:07.188Z_

- Define buyer flow: 402 → wallet pay → retry with payment header
- Pick facilitator (x402.org test vs CDP/PayAI mainnet)
- Set `payTo` on Base; never store signing keys on API host

_…1 more bullets + full lens only on paid POST /v0/outline._

## Metadata
```json
{
  "topic": "x402",
  "tier": "sample-outline",
  "free": true,
  "ladder": [
    "free",
    "outline",
    "brief"
  ],
  "outlinePriceUsdc": "0.01",
  "briefPriceUsdc": "0.02",
  "payTo": "0xE79e7fa7Ce7259C46F9B127b837d2907Bb036F95",
  "network": "eip155:8453",
  "paidPath": "https://x402.devvizion.com/v0/outline",
  "upgradePath": "https://x402.devvizion.com/v0/brief",
  "machineJson": "https://x402.devvizion.com/v0/sample-outline.json?topic=x402",
  "mcp": "https://x402.devvizion.com/mcp",
  "version": "0.3.77"
}
```