curl --request GET \
  --url https://core.nozle.app/api/v1/add_ons/{code} \
  --header 'Authorization: Bearer <token>'

{
  "add_on": {
    "lago_id": "1a901a90-1a90-1a90-1a90-1a901a901a90",
    "name": "Setup Fee",
    "invoice_display_name": "Setup Fee (SF1)",
    "code": "setup_fee",
    "amount_cents": 50000,
    "amount_currency": "USD",
    "description": "Implementation fee for new customers.",
    "created_at": "2022-04-29T08:59:51Z",
    "taxes": [
      {
        "lago_id": "1a901a90-1a90-1a90-1a90-1a901a901a90",
        "name": "TVA",
        "code": "french_standard_vat",
        "rate": 20,
        "applied_to_organization": true,
        "created_at": "2023-07-06T14:35:58Z",
        "description": "French standard VAT"
      }
    ]
  }
}