My 5 year old son asked for a computer for Christmas. Here is how I created a build-at-home-laptop-kit for under $130 that he can assemble by himself.
Raspberry Pi model B ($40) B&M Microcenter
Clear Case ($9 )B&M Microcenter
Motorola Lapdock ($40) used
16GB SD card (Free, spare card I had in "the drawer")
HDMI Micro Female to HDMI Male Adapter ($11)
HDMI Extension Cable ($9)
USB Micro Extension Cable ($14)
USB Micro to Regular adapter ($5)
Optional Wifi Dongle: Tenda m311m ($10 Microcenter) works without any driver hassle.
You can get the cables and adapters much cheaper if you don't have Christmas hanging over your head. I needed everything prime-eligible!
*B&M = Brick and Mortar, as in I got myself into a car and drove to Microcenter.
I used a regular monitor to test and configure the pi and OS.
Made the /boot/config.txt changes mentioned here.
$ sudo nano /boot/config.txt
Find and uncomment or change:
And didn't have to do any power splicing since the latest pi board can be powered by the regular USB ports (so called "backpowering").
I labeled everything so that he can put it together with minimal directions, making sure that the orientations matched. As a bonus I can have him learn about the names of the pieces and write a how-to book for himself over the Christmas break. Fact is my 3 year old could also do this build, but since she can't yet read it's not really appropriate yet.
Next for me is to get gnash running on it so that he can play flash games on kid websites. (Why are flash games still so prevalent in a age where there is no more mobile flash!)
There are some issues with suspend/resume but I don't really care. He should be shutting down after every use.
Another bonus: if I want him to work on something offline (a game I installed or complete a project, I can just take the wifi dongle out.)