1byone Products via Amazon offers its 1byone Easy Chime Wireless Doorbell with two Plug-In Receivers, model no. O00QH-0761, for $15.99. Coupon code "GKBBTZ5Q" cuts that to $12.95. Plus, Prime members bag free shipping. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping costs $6.83.) That's $14 off and the lowest total price we could find. It features 36 chime tones, three chime modes, three volume levels, and a 500-foot operating range.