Until December 15, 2013, Barnes & Nobles stores and BN.com will be offering $10 off when you spend $19.99 or more on Toys & Games using a MasterCard. Excludes LEGO Architecture Studio and LEGO Mindstorms EV3. Remember to bring the coupon with you for in-store purchases. Not bad for picking up some of the $19.99 sets as that would work out to be 50% off!
Thanks to forum members gfeigelstock and snuffles for the heads up.