Factory Authorized Outlet on eBay has the dual fuel generator on sale again for $499 with free freight shipping.
I bought this generator a few years ago. It works fine.The electric start is a nice feature. It runs on either gasoline or propane.
Do your homework if you plan to run this on propane. A bbq grill size bottle is not large enough to run this generator for long periods of time. A larger size bottle is necessary for a sufficient rate of vaporization. Do your homework on propane.
https://www.ebay.com/itm/DuroMax-…ctupt=true