If you planned to do some basic computing experiments that possibly includes both software and hardware integration as well, but wanted all of that to be at a throw away cost, then am sure you would have heard and possibly already being using Raspberry Pi. At a price of just about $ 40, this credit card sized board, along with basic computing power, using an ARM chip, can connect to a regular desktop/laptop and use external keyboard and mouse and allows you to easily program in a language like python (you can also use other languages like C, C++, Java, Ruby, Scratch etc.) The recommended OS is Raspbian but ARM Linux is equally popular. Here’s the list of additional OSs that can be used.
The device can be really useful, as I said earlier, for quick throw away programming. The idea being that you use this low cost device to quickly do some POC and if that works out, you can then plan to go big (commercial) with possibly a full-fledged computer or maybe a tablet device or even a custom design and built PCB. Some time back I got a chance to use this device to interface with a vending machine. It was interesting to program the GPIO ports to generate a voltage signal based on some conditions, and that would in turn trigger the vending machine to dispense an item. You can read more about GPIO programming here.
The second generation of Raspberry Pi is also available now that provides for on-board USB ports, HDMI ports, Ethernet port Micro SD slot and some more features. You can see the details here. There is also a further split in features based on Model A or B. For details see here.
While Windows 8 supported SoC and Windows RT ran on an ARM chip, but it was still not compatible with Raspberry. The memory and CPU requirements to run Windows 8 were higher than what Raspberry supported. However Microsoft seems to have realized that they are missing on a big community by not supporting Raspberry, for they recently announced that Windows 10 will work on Raspberry Pi 2. I am assuming that this will mean that C# and VB.NET will possibly get added to the list of languages one can use to program the device.
An ex-colleague of mine is writing a book on Raspberry Pi and the book is expected to hit the stands next month. I am eagerly looking forward to it and wish him all the best for the book. Will disclose more details once the book hits the market.