Northern Tool offers the NPower 400-watt Wind Turbine for $449.99. Coupon code "257137" drops that to $429.99. Opt for in-store pickup to dodge the $13.99 shipping fee. That's $70 off and the lowest price we could find, although we saw it with a $50 gift card for $450 last July. It's for use with 12-volt or 24-volt systems and mounts on any 1.5" schedule 40 steel pipe. Coupon ends May 22.

Don't mind a gift card? Coupon code "259027" bags a $25 Northern Tool Gift Card. (Coupons don't stack, but it yields a stronger overall discount if you'll be shopping at Northern Tool in the future.)