Amazon Dash button 5 $ - for shopping on amazon, hacks found for ifttt integration ( integrated with buying on amazon) : http://www.amazon.com/b?node=10667898011
https://www.particle.io/button 20 $ , integrated with ifttt
Product: ESP8266 => DIY 7$ IFTTT ( https://www.hackster.io/noelportugal/esp8266-ifttt-easy-butt... , https://hackaday.io/project/5673-esp8266-dash-button , http://www.instructables.com/id/Emergency-Button/ , https://github.com/sam1am/IFTTTButton)
Since this was mentioned elsewhere in the thread, this is actually $49. With a little work, the $19 Photon could certainly do the same.