$250-$500

I'll send a card, but I want to include a monetary gift as well.

How about a card for a former employee? If you prefer to do the check, look at their registry (if they have one) for average price range of items. Send a check of an amount that seems reasonable.

I am honestly past the time I attend many weddings, so I have no idea what's the norm anyway. I didn't attend the wedding, I'll just be sending a check.