Cheap wireless doorbell

I bought the $9 wireless doorbell from BN-Link for a friend whose old doorbell stopped working. The button unit comes with double-sided foam tape and uses a coin battery. The ringer plugs into a wall outlet. Installation took 60 seconds; deciding on which of 58 different chimes to use took 10 minutes and was a lot more fun. I wanted "Rage Over a Lost Penny" based on the title, but my friend decided on "Westminster Chimes." — MF