curl --request POST \
  --url https://api.example.com/cabinet/subscription/purchase-preview \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "selection": {
    "period_id": "<string>",
    "period_days": 1825,
    "traffic_value": 50000,
    "servers": [
      "<string>"
    ],
    "devices": 50
  }
}
'

{}