Massdrop offers the Satechi Bluetooth Button for iPhone in Home or Camera for $18.99 plus $2.55 for shipping. That's the lowest total price we could find for $3. These buttons can be attached to your keychain, steering wheel, or dashboard to access your smartphone when it's out of reach. The Home button activates Siri for calls, directions, or accessing information, while the Camera button operates as a shutter remote for selfies from up to 40 feet away. Deal ends April 5.