Northern Tool offers the NPower 400-watt Wind Turbine for $449.99. Coupon code "253305" drops that to $399.99. Opt for in-store pickup to dodge the $13.99 shipping fee. That's tied with last week's mention, $100 off, 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. Deal ends July 4.