I just got a Wemos D1 mini, which is the ESP8266 board favoured around the Hacklab. It’s a microcontroller with wifi and USB power / serial, about 1.5 GBP from China.
To program it with Arduino, the board files are here: https://github.com/esp8266/Arduino I couldn’t find this at first because the links from the Wemos site are broken. This appears to be a community maintained equivalent.
Once I got that done I had a webserver running very quickly. :)