So in Korea, if you go to any event, like wedding, wake, birthday party, etc, you almost always take an envelope of money. There's absolutely no social stigma in giving an envelope of money, and they actually sell special envelopes for that purpose. Giving gifts other than money is relatively rare, although no one will complain if it's high value enough, like very high name brand bags (LV, yes. Coach, no) or jewelry. A gift certificate is a completely joke gift and people will laugh when they see it and wonder where the real gift is.