It has a quad-core ARM7 SoC at 1Ghz, 1Gb ram, GPU..etc
Microcenter has them in stock at 29.99 and 6 dollars shipping.
The operating system and storage is on a micro SD card. Extra storage can just be plugged into a USB port.
It's a very secure system as you can tweak everything to your liking and save an image of the uSD card... to set everything back exactly as it was just reload the image to the uSD or just have several uSD cards ready to plug in.
I have a version of Debian Linux running on my Pi, a wireless kbrd/mouse, USB WiFi dongle...
I just velcroed the thing onto the back of the HDMI TV :-)