Northern Tool offers the NPower 400-watt Wind Turbine bundled with a $100 Northern Tool Gift Card for $499.99. Opt for in-store pickup to dodge the $13.99 shipping fee. Assuming you use the gift card, that's $50 under our mention from two days ago, $100 off list, and the lowest price we could find. It's for use with 12-volt or 24-volt systems and mounts on any 1.5" schedule 40 steel pipe.