Where to find the rear bumper isolator (foam part)???

Where can I buy the rear bumper isolator (foam part) at a reasonable price???

Hi!

I'm in the process or repairing my damaged Mustang GT 2001. The rear bumper isolator needs to be changed and Ford sells it for 227$ canadian.

That's pretty expensive for a small piece made of foam. Your help would be VERY appreciated! Thanks.