The Raspberry Pi itself comes at a low price, but in order to use it properly you’ll need to buy additional hardware. To avoid that someone runs into material problems or just as a reminder for myself, here is a rather incomplete list of additional hardware you need when buying a Raspberry Pi:
The RPi comes without anything to protect it from the outer world. Therefore you should buy a case to put it in. There are also a lot of people building their own cases, be creative.
Keep in mind that a case should also provide the RPi with enough fresh air, else it will overheat quickly. This is especially important when overclocking the device.
Nothing will happen without power supply. You need a Micro USB power adapter which is capable of providing stable 5V and about 1200 mA. Usual mobile phone adapters will work too, but they’re probably to instable and the RPi will have some hiccups using them.
As the RPi comes without any internal storage, you need to insert a SDHC card (these are the big ones, usually used in cameras). Most operating systems need at least 4GB of memory. You should also look at the speed of the cards, a class 6 card might be cheap, but a class 10 card is worth the money. I bought two 16GB Class 10 cards, that way I’m able to switch between different operating systems.
Don’t forget that you’ll also need to put data onto the card, so make sure that you have a SD-card reader around.
You need to buy some cables for the connections. HDMI is the method of choice for connecting the RPi to a screen. You’ll also need a RJ45 LAN cable to connect the RPi with your router.
Without a keyboard you will have a hard time inputting your data, so order one if you don’t have a spare one flying around the house. A mouse will also come in handy. I choose the Logitech K400 because it’s wireless and has an integrated touchpad. It’s perfect for using it in the living room.
Active USB Hub
There are two reasons to connect an Active USB Hub to your RPi:
At first the Raspberry Pi only provides 2 USB ports, so you’ll probably run out of ports on the long time. The second reason is that the RPi has problems with hotplugging USB, in my case it always crashed when I tried to connect my Wifi dongle to it. A good active USB Hub solves this problem.
If you want to use your RPi as a media center you would want activate the hardware encoding for MPEG-2 and H.264. To do this you need to buy the codec packs from the Raspberry Store. Purchases are processed via Paypal, you’ll get an activation key via Email. With these codecs it shouldn’t be a problem to play 1080i movies on the Raspberry Pie.
For certain usecases you would want to overclock the Raspberry Pi. To avoid grilling the RPi and to extend its lifetime it is needed to apply a passive cooler. There are special cooling solutions available for the RPi, just take some time and see what your merchant of choice can offer. You can cool different subsystems like CPU or GPU.
Don’t forget to buy some cooling paste if not included with your cooler.
As you can see, depending on what you want to do with it, the Raspberry Pi can be more expensive than originally thought. In my case I easily spent more money on additional hardware than on the RPi itself. I think that’s perfectly ok, better then spending more money on the RPi itself and get features you do not need. All in all the RPi is a system to tinker around with, not something which works off the shelve.