To create the Subscription Settings Service in SharePoint 2013 we can use a simple PowerShell script:

$serviceTypeName = "Microsoft SharePoint Foundation Subscription Settings Service"
$accountName = "mydomain\sharepoint.service" 
$appPool = "SharePoint Service Applications"
$serviceName = "Subscription Settings Service"
$serviceDB = "Subscription_Settings_Service"

$service = Get-SPServiceInstance | where { $_.TypeName -eq $serviceTypeName }
Start-SPServiceInstance $service

Write-Host "Service instance started."

# Gets the name of the managed account and sets it to the variable $account for later use.
$account = Get-SPManagedAccount $accountName

$appPoolSubSvc = Get-SPServiceApplicationPool $appPool

if ($appPoolSubSvc -eq $null)
    # Creates an application pool for the Subscription Settings service application. 
    # Uses a managed account as the security account for the application pool.
    # Stores the application pool as a variable for later use.
    $appPoolSubSvc = New-SPServiceApplicationPool -Name $appPool -Account $account

Write-Host "Have the application pool..."

# Creates the Subscription Settings service application, using the variable to associate it with the application pool that was created earlier.
# Stores the new service application as a variable for later use.
$appSubSvc = New-SPSubscriptionSettingsServiceApplication –ApplicationPool $appPoolSubSvc –Name $serviceName –DatabaseName $serviceDB

Write-Host "Service application created..."

# Creates a proxy for the Subscription Settings service application.
$proxySubSvc = New-SPSubscriptionSettingsServiceApplicationProxy –ServiceApplication $appSubSvc

Write-Host "Service application proxy created..."

Write-Host -ForegroundColor green "Done."

Change the variables $accountName, $appPool, $serviceName and $serviceDB so it matches your environment.