Cambond via Amazon offers its Cambond Self-Powered Waterproof Wireless Doorbell Kit with LED Flash in Silver for $24.99. Coupon code "MQWSGWBW" cuts it to $19.99. With free shipping, that's $5 off list and the lowest price we could find, although it was a buck less in September. 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 November 19.