There is a very small PLC ( ladder logic programmable) for only U$69. 6 inputs/ 4 outputs.
Please check

http://www.lt-automation.com

These guys have a lot of very low cost industrial automation products.

 

Not bad, now if they offered Linux tools and a bit more Open, they could be leaders into a vast new market that Big Automation chooses not to address. If you've been watching this space, there is a lot of interest in low cost PLC and PC hybrid automation. And in using Linux to bring things together. Big Automation is not well positioned to address this market as they are fully committed to the luxury class and deeply invested in the MS only schema. A little reimaging as Open low cost innovators rather than the cheap alternative would more accurately target and exploit this trend. There's an enormous potential market and a lot more room for growth at the low end. Sorta what PCs did to the high buck minicomputer and low end mainframe market.

Regards

cww