For a few cents more than the ESP12F you get it with a programmer daughter board, a RGB led, a button and a photoresistor. This is ideal for small robot with networking abilities. Can be programmed with Arduino IDE as a NodeMCU v1.0 .
This is a companion discussion topic for the original entry at https://community.robotshop.com/index.php/blog/show/an-even-cheaper-wi-fi-board