$8 to Enter the Microcontroller Game

Yep you heard me. $8. STMicroelectronic’s STM8S-Discovery will go for that price. Not only that but all the development tools are available for download. –

The STM8S-Discovery kit, is the cheapest and quickest way to discover the STM8S, to build and debug the application, and to program and use the device.
The STM8S-Discovery is a quick-start evaluation board based on the STM8S105C6T6. It includes the embedded debugger ST-LINK and one touch-sensing button which help you to discover the STM8 features.
Plug STM8S-Discovery into a PC through a standard USB cable, and run the proposed example. Once the debugger is open, you will see the real-time execution of the code.
Numerous applications are available in order to learn, reuse and modify codes for a fast time to proof-of-concept or demonstration.
It will satisfy hobbyists, developers, students and support teams. Based on examples, you will find STM8S-Discovery indispensable.

At $8 that beats most dedicated circuit designs of anything beyond a 555IC and some caps. At a pin out to a relay board and you could very cheaply control practically anything out there.

More here.