I'm assuming you mean the M-B OEM bumper mounted fog lights. When I looked at this for our MBS I was told by my local M-B dealer I couldn't afford them...
Lights, bulbs, wiring, different hardware, computer update (CANBUS), a new bumper plus labor was well over $2K!
They weren't meant to be a dealer installed option and there wasn't a kit when I checked on it.
Suggestions? There are a lot on high quality fog light kits that will easily mount under your bumper. I've used Hella lights in the past and had excellent results. I would check with your M-B dealer on wiring them to prevent any CANBUS issues. The less you touch the M-B wiring the better off you'll be...
Welcome to the forum and congratulations on your Prism!