My sister wants a new computer. I decided to put together the cheapest possible parts for a $200 build. Would have been under $200 but I put in the Coolermaster 2-pack fans. Only $10 more.
http://pcpartpicker.com/p/nXIV
Can you do better?
PS: All she does is listen to music, play with MS Paint, and surf the web. We'll be stealing the optical out of her current (windows 95) pc.
Edit: It could even be one of those Raspberry-Pi things. I don't know much about them, but I do know she could just use a USB Optical.
Why don't you just go on eBay and look for some cheap computers - there is some proper cheap refurbished stuff that will be fine for what your sister wants