Factory Authorized Outlet via eBay offers the Duromax 8,000-watt Dual-Fuel Portable Generator, model no. XP10000EH, for $499.99 with free shipping. That's $200 under our June mention and the lowest total price we've seen. (It's the best deal now by $432.) This generator runs on propane or gasoline and provides a constant 8,000 watts of power with a 10,000-watt max output.