They sell standing room for sold out shows, but beware if you're short. You can see over the two center section walls if you're anything over 5 feet, but the side section is a good six inches higher than that.
Keep on eye on Stubhub/TickPick. I was able to purchase 2 premium seats for $40 each for a Friday night performance 45 minutes before curtain. The ticket was worth $299. Orchestra Row J 113-114 inner aisle.