Northern Tool offers the NPower 400-watt Wind Turbine for $449.99. Apply coupon code "255178" to bag a $50 Northern Tool Gift Card. Opt for in-store pickup to dodge the $13.99 shipping fee. Assuming you'll use the gift card, that's tied with our December mention as a savings of $100 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. The gift card expires on October 31.