curl --request GET \
  --url https://api.fourthwall.com/open-api/v1.0/promotions/{promotionId} \
  --header 'Authorization: Bearer <token>'

{
  "id": "<string>",
  "code": "<string>",
  "discount": {
    "percentage": 123,
    "type": "<string>",
    "money": {
      "value": 10,
      "currency": "USD"
    },
    "freeShipping": true
  },
  "requirements": {
    "minimumOrderValue": {
      "value": 10,
      "currency": "USD"
    }
  },
  "usageCount": 123,
  "limits": {
    "maximumUsesNumber": 123,
    "oneUsePerCustomer": true
  },
  "appliesTo": {
    "type": "<string>"
  },
  "type": "<string>",
  "title": "<string>"
}