Cambond via Amazon offers its Cambond Self-Powered Waterproof Wireless Doorbell Kit with LED Flash in Silver for $26.99. Coupon code "OFVEJLDP" cuts it to $19.99. With free shipping, that's tied with our mention from three weeks ago, $5 off list, and the lowest price we could find. It features a 500-foot wireless range, one transmitter powered by battery-free kinetic technology, two plug-in receivers, 58 ringtones, four volume levels, and four sound/LED modes. Deal ends December 9.