Adafruit HUZZAH ESP8266 Breakout : ID 2471 : $9.95 : Adafruit Industries, Unique & fun DIY electronics and kits
High Quality Esp8266 Esp-01s Serial Wifi Module Replacement For Esp-01 - Buy Módulo Wifi Esp8266 Módulo Esp8266 Esp8266-01s Módulo Serial Wifi Esp8266 Product on Alibaba.com
ESP8266 todo lo que necesitas saber del módulo WiFi para Arduino
Amazon.com: DIYmall ESP8266 ESP-01S WiFi Serial Transceiver Module with 4MB Flash : Electronics