Go to your local shop and tell them you are buying 3 of them. I see you are in MA, drive up to RC Buyer's Warehouse in Nashua, NH and talk to them, they;ll probably cut you a deal, plus no sales tax.
If you want to mailorder, and stay in the states, Heliproz and Rick's both have them for $330. Buy from them if warranty is of importance to you (it is to me, UPS should deliver mine from the 'proz today.)
If you don't care about the warranty, http://www.rc-mushroom.com
is reliable and has the best price, $245.