Sparkfun’s ESP8266 Thing (as in “Internet of Things”) is an inexpensive board for creating a Wi-Fi enabled electronics project.
Designed around the EPS8266 Wi-Fi chip, Sparkfun has provided an Arduino add-on and library to simplify programming as well as providing detailed examples for posting data to data.sparkfun.com, their cloud platform for posting sensor data, similar to Adafruit’s IO. You can however send or serve your data anyway you like.
The board also makes using LiPo batteries easy, with headers for the battery and charging through micro-USB, allowing your project to be completely wireless.
The Thing may not be for everyone. You’ll need to purchase a USB to Serial cable or adaptor to program it. The Micro-USB port is for power and charging only. You will also need to solder on headers to use the board’s IO pins. This can be an advantage that gives you more flexibility when building your project. It also has fewer IO pins compared to some boards, but if you are using I2C you should be fine.
This board would be great for setting up a sensor network or controlling household electronics, and it is inexpensive enough to have a few of your own things on the internet.