Amazon with AnkerDirect has the Anker Powerhouse II 400 Portable Power Station (A1730) for $400 - $100 off coupon (check green "Save coupon" box) = $300 with free shipping.

388Wh capacity generator alternative can charge up to 8 devices simultaneously and has a 300W AC outlet, 60W USB-C port, 3 USB-A ports, a car socket, and 2 DC ports.