500ft BESTEK Wireless Doorbell Kit $6.99 @Amazon

https://www.amazon.com/dp/B06ZYCV9X9

Coupon code: 97BE2JBQ
(Code seems work on all options and price range is $6.99-$13.99)

Wireless Range up to 820 ( 250m ) Feet in open space, 36 Chime Options, 4 levels of adjustable volume 110dB±5dB, Easy to install
Long Range Operating: up to 500 feet working range(820 feet in open area), either you are occupied in the garden or at the kitchen, the wireless doorbell reminds you that someone is calling from outside.
High Quality Speaker with Good Voice System: Adopt high quality Φ29 speaker, the wireless doorbell provides better and louder voice apart from traditional speaker, ensures that you will never miss any visitors. Comes with 36 different ring tones with 4 levels of adjustable ringing volume(High / Medium / Low/ Mute), 110dB5dB, you can choose the chime you like.
Pass Cold and Hot Weather Test: This wireless doorbell can work normally in -15℃ and 55℃ temperature, free from bad weather problem. With 18 months warranty and easy reach friendly customer service, you can totally buy the doorbell with confidence!
Expandable and Easy Installation: Each receiver can be worked with up to 4 push buttons, and each button can be worked with multiple receivers. The transmitter comes with over 1million frequency code which will not interfere with other equipment in your home or those of your neighbors. ( NOTE: NO batteries required for main receiver)
WHAT YOU GET: 1 X Transmitter 1 X Receiver 1X 3M Sticker X1 Batteries