You should be able to get a ~1 year old MacBook for that price (new ones are about $1000); might even find one with a year left on the AppleCare warranty.
Search eBay for MacBook and you will find some with live AppleCare.
Good luck!
Best,
Kurt
Here's a good example, sold for just over $800 with AppleCare into 2009 (item # 300190515323):
http://cgi.ebay.com/Macbook-1-83-Ghz-1GB-Ram-60GB-HD-AppleCare-Warranty_W0QQitemZ300190515323QQihZ020QQcategoryZ1 40064QQssPageNameZWDVWQQrdZ1QQcmdZViewItem