Northern Tool offers the Mr. Heater Big Maxx 80,000-BTU Natural Gas Garage / Workshop Unit Heater for $398.99. Coupon code “261282” bags a $25 Northern Tool Gift Card. (It must be redeemed by June 30.) Choose in-store pickup to dodge the $50.49 shipping charge. Assuming you’ll use the credit, that’s the lowest price we could find by $44. It can heat rooms of up to 2,000 square feet. Deal ends February 24.