REI offers its REI Connect Tech Tent Vestibule in Sage/Platinum for $34.99 plus $5.99 for shipping. That's $15 off and the lowest total price we could find. It's compatible with 2011 Hobitat 4, 6, and Kingdom 8 tents, and all 2012 and later Hobitat and Kingdom tents, and adds 31.6-sq. ft. of weatherproof storage.