Ebay offers Refurbished Firman 4,000W Electric Start Dual Fuel Inverter Generator for $399.99 (reg $589.99) with free shipping.

Product Description:
The FIRMAN WH03242F is a 3200/4000W 30A electric start RV-ready portable generator, running on both propane and gasoline for the best of both worlds.

• The WH03242F is a part of the Whisper Hybrid Dual Fuel Generator Series. It runs at a quiet 58dB, well below National Park standards.
• It's the ideal solution for those on the go and those who enjoy camping, tailgating, and other recreational activities. Enjoy clean, renewable, quiet power on the go with the WH03242F.
• FIRMAN Refurbished generators have a limited 90-day warranty.