Just bring a "from" tag with your name on it and swap one out at the gift table - no one will know
I say:
Non Family - $100
Family - all depends how close you are - from $100-$500
Give what you want and are comfortable with!
Google - Wedding Gift Etiquette (tons to read)
pulled this off a site:
There’s a rumor floating around that the cost of a wedding gift should equal the cost of the guest’s meal. This is not true. The gift giver can give whatever she chooses, no matter how much the hosts spent on dinner. Whether ten or one thousand dollars is spent on a gift, the bride and groom should accept it graciously and appreciate the thought.