curl --request GET \
  --url https://api.gcore.com/cloud/v1/instances/{project_id}/{region_id}/{instance_id}/available_flavors \
  --header 'Authorization: <api-key>'

{
  "count": 1,
  "results": [
    {
      "architecture": "x86_64",
      "capacity": 1,
      "currency_code": "USD",
      "disabled": false,
      "flavor_id": "g2-standard-32-64",
      "flavor_name": "g2-standard-32-64",
      "hardware_description": {},
      "os_type": "linux",
      "price_per_hour": 1,
      "price_per_month": 720,
      "price_status": "show",
      "ram": 2048,
      "vcpus": 1
    }
  ]
}