Yeesh... linux, freeware, monitor somewhere else, have someone build it... I got the impression that an inexpensive turnkey system might be more in order here. Sounds to me like Sue would like to buy something you can take out of the box, plug it in and use it. And have one place to call for questions.

First I'd call the school. It is likely they have a recommended setup. For example, a PC running XP with this software suite on it and a printer. Something like that. Then I'd call Dell (personal preference) and talk to someone there. Read them the list and have them give you options and the bottom line price.

For a kid I'd recommend a laptop. They're going to want to connect to the internet so I'd recommend getting the wireless option (probably included anyway). If you get internet access in the home a wireless access point is not an expensive option and allows using the laptop anywhere in the home. Also allows one to access the internet at the "hotspot" access points that are cropping up everywhere. Depending on the cost of the machine their warrantys aren't bad either (accidental damage might be appropriate for a kid). $650 would get you a 15" laptop with Vista, MS Office word, excel + powerpoint (wireless built in). One stop shopping and and support and you know you'll have everything you need.