There's also the WeMos boards, which can be had for $3-4. Those are my workhorses. http://www.cnx-software.com/2016/02/19/4-wemos-d1-mini-esp8266-board-support

There's also the WeMos boards, which can be had for $3-4. Those are my workhorses. http://www.cnx-software.com/2016/02/19/4-wemos-d1-mini-esp8266-board-supports-shields-with-a-temperature-sensor-a-button-a-relay-or-a-micro-sd-slot/ http://www.cnx-software.com/2016/02/19/4-wemos-d1-mini-esp82...