Hobbykingmall via Amazon offers the QuadPro Brain Flakes 570-Piece Building Set for $19.99. Coupon code "QuadPro6" cuts it to $13.85. Plus, Prime members receive free shipping. That's $6 off, tied with our mention from two weeks ago, and the lowest price we could find. This BPA-free set includes 570 brain flake building blocks, four wheels, a building booklet, and storage pocket. Deal ends June 19.