Factory Authorized Outlet via eBay offers the DuroMax 3,500-watt Gas-Powered Generator, model no. XP4400E, for $319.99 with free shipping. That's the lowest total price we could find by $75. Its power panel features an RV switch, keyed electric start, engine shutoff switch, volt meter, and circuit breakers. It produces a 4,400-watt surge and 3,500 watts of continuous power.