Yugster offers this Liger Waterproof Wireless Doorbell Kit for $9.97. Coupon code "FreeYugBuck" drops it to $8.97. With $2 for shipping, that's $31 off list and the lowest total price we could find. It features 38 chimes and has a range of 325 feet.
Note: The countdown timer on the product page does not reflect an actual expiration time and resets daily