Hobbykingmall via Amazon offers Prime members the QuadPro Brain Flakes 570-Piece Building Set for $17.99. Coupon code "QUADPRO9" drops it to $11.99. With free shipping for Prime members, that's tied with our October mention and the lowest price we could find by $9. This BPA-free set includes 570 brain flake building blocks, four wheels, a building booklet, and storage pocket. Deal ends December 10.