Kmart.com currently has LEGO Ninjago 70504 Garmatron for $21 (reg.$39.99). Savings work out to be 48% off. Its not available for sale online, but you can order it via store pickup. Thanks to forum member Eek for the heads up.
Plus, you can also use coupon code KMARTMUST for an additional $5 off $45. As always, Kmart offers FREE Shipping to store or FREE shipping to home on orders above $59. If the item is not available online, you can also try store pickup.