On another thread you asked where Roof Airs are availiable for about $650.00.
I just purchased a Dometic Penguin 13,500 BTU air conditioner for $642.00 plus $44.94 Indiana sales tax. Total price $686.94 from RV Surplus in Elkhart, IN. The unit is brand new with factory warrantee. I picked it up to save on frieght but when you pick it up you have to pay the sales tax. Shipping can be pricey but trade off is no sales tax. There phone is 574-264-5575.