Northern Tool discounts a selection of stationary air compressors, with prices starting at $569.99. Plus, take an extra $20 off via coupon code "254876", which drops the starting price to $549.99. Even better, almost all of these items receive free shipping; otherwise, shipping starts at $121. Deal ends October 17. A couple of best bets, both with prices after coupon and free shipping: Note: Free shipping requires you unload this item from the truck yourself. If you do not have the means to safely unload this item, lift gate service incurs an additional charge. Choose in-store pickup where available to dodge this fee.