curl --request GET \
  --url https://{defaultHost}/v5/app/line_items/{id} \
  --header 'Authorization: Bearer <token>'

{
  "id": "<string>",
  "created_at": 123,
  "company_id": "<string>",
  "app_id": "<string>",
  "name": "<string>",
  "description": "<string>",
  "amount": 123,
  "base_currency": "usd",
  "allow_multiple_quantity": true,
  "metadata": {}
}