I did some Googling today.
And found that you can add WiFi to your project for only $3.
I’m talking about the ESP8266 module. It’s a WiFi module you can connect to an Arduino – or some other microcontroller.
It’s usually $5 or more.
But today I checked aliexpress.com and found someone who sold it for only $3!
You can control it by sending commands over the UART interface. The documentation is in Chinese, which can be a challenge for some of us ;) But there are people experimenting with it and translating into English.
I played around with it in Berlin at a workshop a few months ago. It was really cool.