Factory Authorized Outlet via eBay offers the Generac LP 3,250-watt Liquid Propane Portable Generator for $399.99 with free shipping. That's the lowest total price we could find by $209. It features a 212cc air-cooled engine, 9.5" wheel kit, and low-oil shutdown.
Note that this accommodates a 20-lb. tank, but the tank is not included.