How much should it cost to replace the scuttle and what does it do? on 2004 Volkswagen Passat

The scuttle (the plastic part that covers the front underside of the car) came loose and now part of it is missing.

Asked by for the 2004 Volkswagen Passat
Is this part located on the lower part of the front bumper?
I think its called an Undercar Shield $283 available at :
Yes, it is on the bottom side of the engine but not part of the bumper.
1 more answer
Good grief, don't replace it with plastic crap!

Read this:

Mine was $280 SHIPPED, it took less than 20 minutes to install this peace of mind.