curl --request GET \
  --url https://api.paygentic.io/v0/plans/available \
  --header 'Authorization: Bearer <token>'

{
  "data": [
    {
      "id": "plan_t9u0v1w2x3y4z5a6",
      "object": "plan",
      "billingInterval": "monthly",
      "createdAt": "2024-01-12T10:00:00Z",
      "currency": "USD",
      "defaultTaxCode": "eservice",
      "defaultTaxRate": 8.5,
      "description": "Claude API access with 500K tokens monthly allowance",
      "invoiceDisplayName": "LLM API Basic Plan",
      "merchantId": "org_b7c8d9e0f1g2h3i4",
      "name": "Basic Tier",
      "price": "49990000000",
      "prices": [],
      "productId": "prod_j5k6l7m8n9o0p1q2",
      "taxBehavior": "exclusive",
      "updatedAt": "2024-01-12T10:00:00Z"
    }
  ],
  "pagination": {
    "limit": 10,
    "offset": 0,
    "total": 1
  }
}