Varies SO much, anything from about 200-500

At least it can take a few knocks then though.
My genuine 500 bumper took a big whack when my car was written off and there was only a slight crack on the bumper which we repaired, if that was a fibreglass one it would be in a million pieces.

You pay more for the original ones, but at least they stay worth something long term and dont ever need replacing unless you have the sort of accident that rights the car off anyway!