Factory Authorized Outlet via eBay offers the DuroMax 3,500-watt Portable Gas-Powered Generator, model no. XP4400, for $279.99 with free shipping. That's the lowest total price we could find by $102. It produces a 4,400-watt surge and 3,500 watts of continuous power. It runs for up to eight hours at a 50% load. Deal ends July 4.