Cambond via Amazon offers the Cambond Wireless Waterproof LED Door Bell in Silver for $21.99. Coupon code "59CFULY4" cuts it to $16.99. Plus, Prime members get free shipping. That's $1 under our mention from three weeks ago, $5 off, and the lowest price we could find. It features two receivers (each with a range of 500 feet), 58 ringtones, and four volume levels. Deal ends December 24.