Hulislem via Amazon offers the Cylen Home Ventilated Memory Foam Orthopedic Seat Cushion in Blue for $26.97. Coupon code "Q9O5EGJG" drops it to $13.75. With free shipping, that's tied with our June mention as the lowest price we've seen. (It's the best deal now by about $17.) It features memory foam with an activated charcoal-infused bamboo core, an anti-slip bottom, and removable washable cover. Deal ends October 31.