The pi can be brought from both Farnell and RS Components. It comes in two flavours: A and B. The difference between the two is the addition of a network connector on the B board along with twice the ram, which adds about £5 to the price and quite a bit to its power footprint. If you are planning on using the pi as a desktop computer, you probably want the model B board. However, if you are planning on using it in robotics etc. then the lower power consumption of the A board is probably a clincher.
Most people who buy a Raspberry Pi will buy it as a bare bones system, which includes just the computer. To this they will add old bits and pieces they have lying around to make it useful. The bare bones system comes without a case, so for many people their first pi project is making one. Check out my Raspberry Pi Cardboard Case for a quick and very cheap way to make a case, or just let your imagination run wild (failing that, you can, of course, just by one!)
To the pi and case, you will need to add at least a sdcard (possibly from an old mobile phone or camera, or purchased new for a couple of quid) to act as its main hard drive (the place where it stores information) and a psu (power supply), for which the pi uses mini usb (the same standard used for mobile phones, e-readers, mp3 players etc.), so if you don’t have a charger spare (and don’t want to power it by plugging it into a usb port on another computer), you’ll have to spend another couple of quid on a phone charger.
If you’re planning to use the pi as a server, all you need is a network cable (or wifi usb adapter) and you’re good to go. To use the Raspberry Pi as standard desktop computer, you’ll also need a monitor/tv, keyboard and mouse.
To connect to a monitor/tv the pi use HDMI (for modern monitors/tvs) and composite (for older tvs). This, unfortunately, means that if you have an old computer monitor you were hoping to use that has a D-Sub connector (and, hence, an analogue VGA signal), you are out of luck. HDMI is digital and a HDMI to D-Sub converter will set you back more than a secondhand monitor. If, on the other hand, your old monitor uses DVI (a digital signal), a two pound converter will do the trick.
As for peripherals, the pi uses the standard usb port, so if you want to use an older PS/2 mouse and keyboard you will again need an adapter, but otherwise, you are probably good to go. Bear in mind, though, that it isn’t just enough for the device you want to attach to the pi to be a USB device. The pi has to have the necessary software to control it (unless you plan on writing your own!) Most standards compliant devices are going to be ok, as are those more esoteric ones that say they are supported by Linux, but it would be good idea to check the Raspberry Pi forums before making any purchases (wifi adapters especially).
If you have something more exciting planned for your pi and are looking at using the GPIO, I will assume that you know what you’re doing(!)
If you don’t have a convenient box of old computer bits and don’t want to shop around on the web for the best deals, don’t worry. You can purchase the pi with all the peripherals.
So go spend money. I’ll see you again once your Raspberry Pi arrives and show you how easy it is to install software on it by taking you through a few simple projects: a NAS Box (file server), media centre, standard desktop computer and time lapse camera. We’ll then have a bit of look at doing some programming on the thing before building ourselves a robot 🙂