rc-angel via eBay offers the Voye 2-Chime Wireless Plug-In Doorbell Kit for $11.98 with free shipping. (Choose 2-chime, 1-button plug-in to see this price.) That's the lowest total price we could find for such a kit by $1. It includes 38 tones to choose from, two plug-in chimes, and a wireless doorbell button. A 12-volt battery for the button is included.