batch rename - Bulk Folder Renaming Powershell Script

The script below is used for Bulk Folder Renaming.

However I wanted to make this as a Generic Script so users can give input and use it accordingly.

1. This script has 3 inputs
   
   
   
   • a) Enter the Source Folder path
   
   
   • b) Extension of the Files and
   
   
   • c) New File Name to be renamed
   
   

All are fine except the c) New File Name to be renamed

$Rename = input
$newName = '$Rename_{0:d6}{1}' -f  $i , $extension  # $rename input cannot be used here #

I think some thing wrong on the above line, is there any way to get this done?

Write-Host "Renaming Bulk Files" -BackgroundColor Green -ForegroundColor White
$Source = Read-Host "Enter the Source Path Of the Folder, Ex: D:\Test"
$SourceExtension = Read-Host "Enter the Destination File Extension, Ex: *.pdf or *.jpg"
$Rename = Read-Host "Enter the File Name to be renamed"
$i = 0
Get-ChildItem -Path $Source -Filter $SourceExtension |
ForEach-Object {
    $extension = $_.Extension
    $newName = '$Rename_{0:d6}{1}' -f  $i , $extension
    $i++
    Rename-Item -Path $_.FullName -NewName $newName
}